Showing posts with label Camera. Show all posts
Showing posts with label Camera. Show all posts
Thursday, August 4, 2011
Wednesday, February 23, 2011
CANON POWERSHOT SX120is
CANON POWERSHOT SX120 is 10-MEGAPIXEL DIGICAM, 10X ZOOM + 4GB CARD + CASE + BATTERY CHARGER + 3 YEARS ALL INDIA NATIONAL WARRANTY.
The Canon PowerShot SX120 IS is a high quality, easy-to-use digital compact camera with a 10x optically stabilised zoom lens. To capture every detail, the PowerShot SX120 IS includes a 10 Megapixel sensor with Canon’s powerful and intelligent DIGIC 4 processor – ensuring superb response times and natural colour reproduction. DIGIC 4 also takes care of difficult lighting conditions with i-Contrast – a technology which prevents highlight blowout, whilst retaining shadow detail. For trouble free shooting the Canon PowerShot SX120 IS includes Smart Auto and Easy modes with Scene Detection Technology. More experienced users can choose their settings with additional shooting modes such as Aperture Priority and Shutter Priority. A full manual control mode is also provided – perfect for users who wish to experiment with their shots. The camera can also shoot VGA movies with sound.
Features:
- 10.0 Megapixel CCD
- F2.8-4.3, 10X optical zoom lens, 36 - 360 mm
- Optical image stabilization
- 3-inch LCD display with 230,000 pixels
- Full manual controls + Smart Auto mode
- VGA movie mode with sound
- SD/SDHC/MMC/MMCplus/HC MMCplus slot; 128MB card included
Salient Features for Canon Powershot SX120IS
More Powerful Features • PowerShot SX120 IS is your best choice if you are looking for an affordable camera with manual controls and zoom powers.
Smart Auto shooting mode with Scene Detection Technology • Smart Auto mode uses Canon’s latest Scene Detection Technology to determine subject brightness, contrast, distance and overall hue, including the ability to differentiate between day-time and low-light (night time) scenarios for an effortless capture of the perfect picture. • The Smart Auto shooting mode intelligently selects the proper settings for the camera based on 18 pre-defined shooting situations.
For All Your Shooting Needs • 1cm Macro for a more personalize shooting perspective • 10x super optical zoom lens with Optical Image Stabilizer for rock steady shots
A Camera For Everyone • First time Digital Camera Photographers In Easy mode, only the shutter button and zoom lever is accessible. The camera will automatically adjust to optimal settings. Flash will automatically pops up when required. • Beginner Photographers In Auto mode, the camera intelligently detects 22 different scenes for a brilliant picture in all conditions. Be it during night time, backlit, subject motion, portrait, etc. • Serious Photographers Users can create the image they want to shoot by adjusting their own shooting modes. - M (Manual) – Full creative control to capture images that best express your vision rather than leave the controls to the camera. - Av (Aperture Priority) - Set the aperture to create the depth of field (the area of focus) and the camera automatically selects the shutter speed. - Tv (Shutter speed priority) - Create a flowing effect to express the passage of time with moving subjects. - P (Program) - Access advanced exposure compensation features while shooting mostly - Auto - The camera chooses all the settings so you can concentrate on your subject.
Standard Accessories for Canon Powershot SX120IS
- Canon PowerShot SX120IS
- Wrist Strap
- AA-type Alkaline Batteries (x2)
- AV Cable
- USB Cable
- Canon Digital Camera Solution CD-ROM
- User Guides
- 4GB card
- case
- Battery charger
More Powerful Features
•
PowerShot SX120 IS is your best choice if you are looking for an affordable camera with manual controls and zoom powers.
Smart Auto shooting mode with Scene Detection Technology
•
Smart Auto mode uses Canon’s latest Scene Detection Technology to determine subject brightness, contrast, distance and overall hue, including the ability to differentiate between day-time and low-light (night time) scenarios for an effortless capture of the perfect picture.
•
The Smart Auto shooting mode intelligently selects the proper settings for the camera based on 18 pre-defined shooting situations.
For All Your Shooting Needs
•
1cm Macro for a more personalize shooting perspective
•
10x super optical zoom lens with Optical Image Stabilizer for rock steady shots
A Camera For Everyone
•
First time Digital Camera Photographers In Easy mode, only the shutter button and zoom lever is accessible. The camera will automatically adjust to optimal settings. Flash will automatically pops up when required.
•
Beginner Photographers In Auto mode, the camera intelligently detects 22 different scenes for a brilliant picture in all conditions. Be it during night time, backlit, subject motion, portrait, etc.
•
Serious Photographers Users can create the image they want to shoot by adjusting their own shooting modes.
- M (Manual) – Full creative control to capture images that best express your vision rather than leave the controls to the camera.
- Av (Aperture Priority) - Set the aperture to create the depth of field (the area of focus) and the camera automatically selects the shutter speed.
- Tv (Shutter speed priority) - Create a flowing effect to express the passage of time with moving subjects.
- P (Program) - Access advanced exposure compensation features while shooting mostly
- Auto - The camera chooses all the settings so you can concentrate on your subject.
Saturday, December 4, 2010
Macro Photography
Macro Photography
how to take close-up pictures of small things
What Kind of Camera
Point and shoot digital cameras can have remarkable macro capabilities, but for best results you want a single-lens reflex camera. These allow you to attach special-purpose macro lenses and show you in a bright optical viewfinder what you will get on the sensor.
A typical setup might be a Canon Digital Rebel XTi (Black) (review) with a Canon EF-S 60mm f/2.8 Macro USM (review). This lens is designed for the small-sensor Canon cameras and gives a working distance equivalent to 100mm on a full-frame camera. The lens is specified to focus down to "1:1" or "life size". This means that the smallest object you can photograph that will extend to the corners of the final digital photo will be the same size as the sensor inside the Canon Rebel camera, 15x22mm. A professional photographer might use Canon EOS 5D (review) and a lens designed for full Canon EF 100mm f/2.8 Macro USM (review). Confusingly, this lens is also specified to focus down to "1:1", but this time the sensor is 24x36mm in size, the old 35mm film standard. So you can't take a photo of something quite as small as with the cheaper equipment.
In the film world, the 35mm camera systems had comprehensive range of macro lenses and accessories and some medium format systems, such as the Rollei 6008 would have at least a few lenses and extension tubes. Only the extremely patient ever did macro photography with a 4x5 inch view camera.
Doing it all with a Normal Lens
In the good old days a 35mm single-lens reflex camera came with a 50mm "normal" lens. These lenses were extremely light, rugged, and high quality, so naturally the consuming public abandoned them for heavy, fragile, low quality zooms. But that's another story... Anyway, suppose that you are out in the woods with your Canon EOS 5D, a full-frame camera and a 50mm normal lens, and you want to take a picture of the tip of a pine needle. [Everything in this section applies equally to using a 30mm prime lens, e.g., Sigma 30/1.4, on a small-sensor camera such as a Canon Rebel or Nikon D-series.]
First, though, you want to take a picture of the moon. That's pretty far away, so you feel comfortable setting the lens focusing helical to "infinity". The "nodal point" of the optics will now be 50 millimeters from the plane of the sensor. [Note: exposure for the moon should be roughly f/11 and 1/ISO-setting.]
The effort of setting up your tripod is so great that you become tired and fall asleep. When you wake up in the morning, there is a bear standing 10 feet away. You refocus your 50mm lens to get a picture of the grizzly. As you turn the helical from "infinity" to "10 feet", notice that the optics are racked out away from the sensor. The nodal point is a bit farther than 50 millimeters from the sensor plane. The lens is casting an image circle somewhat larger than the 24x36mm sensor. Some of the light gathered by the lens is therefore being lost but it isn't significant.
After snapping that photo of the bear, you notice that his fangs are glistening. These aren't going to appear very large in your last shot, so you move up until you are about 1.5 feet from the bear. That's about as close as the lens helical will let you focus. The nodal point is now pretty far from the lens. Extra light is spilling off to the edges of the frame , but still not far enough to require an exposure correction. The bear's face is 1.5 feet high. You've oriented the camera vertically so that the face fills the 36mm dimension. 36mm is about 1.5 inches. So that means you are working at "1:12". The subject is 12 times the size of the subject's image on the sensor.
You're losing some light, but also you notice that you don't have too much depth of field. A 50mm lens focussed down to a foot from the subject only has a depth of field of 1/16th of an inch at f/4. No problem. You haul out a big electronic flash and stop down to f/11. Now your depth of field is a whopping ... 1/2 inch.
Looking down, you become fascinated by some pattern's in the bear's claws. Each one is about 1.5 inches long. You'd like to fill the sensor's long dimension (36mm) with a claw, which means that the subject and its image will be the same size. You want to work at "1:1". But the folks at the lens factory skimped on the helical. You can't rack your optics out far enough to focus at 1:1. It looks like that pine needle tip photo is completely out of the question.
Why did Canon limit your ability to focus close? For starters, at 1:1 the lens would be so far away from the sensor that it would cast a huge image circle. The standard 24x36mm frame would only be a tiny fraction. So only about 1/4 of the light gathered by the lens would reach the film, i.e., you'd have a two f-stop underexposure if you used the same exposure setting that you'd used for the picture of the bear when he was 10' away. A scene that required a lens setting of f/16 at infinity would require a lens setting of about f/8 at 1:1. All this other light would be bouncing around inside your camera and lens, reducing contrast. Finally, a fixed stack of optical elements can't be designed to form sharp images at so many different focussed distances.
Close-Up Lenses
Your eyes don't focus so great on really small things either. Do you try to pull your cornea a foot away from your retina? No. You stick a magnifying glass in front of your cornea. You can do the same thing for your normal lens. Unlike your cornea, it even has convenient threads for attaching a magnifying glass. The magnifying glass screws into the same place where a filter would go.
A camera store could never sell you a "magnifying glass" for $50 so they call these things "supplementary lenses" or "close-up lenses". Good things about close-up lenses:
At right: a model of Sacre Coeur, captured with a Minolta 50mm lens and single-element Minolta-brand close-up lens. Perhaps not the world's best image, but keep in mind that the photographer was 11 years old at the time of exposure.
Macro Zoom Lenses
Macro zoom lenses are not macro lenses. They don't allow significantly greater magnification than a 30mm or 50mm normal lens and they deliver low quality.
Macro Lenses
What you want is a macro lens. Fortunately, it is difficult to buy a bad macro lens. This is kind of odd in a world where 90 percent of the lenses sold are bad. Perhaps it is because anyone in the market for a macro lens is already fairly sophisticated and quality-conscious. Partly it is because it is easier to make a single focal-length lens than a zoom.
The best macro lenses are the latest autofocus mount models made by Canon and Nikon, typically in focal lengths ranging from 50 to 200mm. Each lens will focus continuously from infinity to 1:1. You can shoot the moon and capture the bear claw without stopping to change lenses or screw in filters. How do these lenses work? Do they just have a much longer helical than the 50mm normal lens? Yes and no.
Yes a macro lens helical has much more travel than a normal lens helical. You can watch the front element move an inch or two. However, these helicals aren't just pushing a stack of glass back and forth like the 50mm's helical. Inside one of the elements is moving ("floating") so that the optical design changes to a more appropriate one for close-up photography. Thus you get sharp images at all focussed distances.
How do you choose a focal length? The same way you do with a non-macro lens. If you can't get very close to your subject at a soccer game, you don't pull out a normal lens; you bring out a 300mm telephoto lens. If you can't get close to an insect without it getting scared and flying away, then you want the 200mm lens and not the 50. If you want to compress features in a woman's face, you use a 105mm lens rather than a short wide angle lens. It is the same with macro work; longer lenses give you a flatter perspective.
At right is an image (from my Christina page) taken with an older design Canon EF 50mm f/2.5 Macro, $265. This lens incorporates a floating element for high image quality, but only goes to 1:2 without a "life size converter" (sort of like a telextender) that you stick between the lens and the camera. The 50 is also annoying because it has the ancient non-USM Canon motor. So it can't do simultaneous AF and MF like the ring-USM lenses.
Check the Canon and Nikon system pages for a current list of all the macro lenses made by those companies for their bodies.
Sigma, Tamron, and Tokina make excellent single focal length (prime) macro lenses. If you're using a system other than Canon or Nikon, these may be better quality than your own manufacturer's lens. If you're using Canon or Nikon, you might be able to save a few dollars, at the expense, perhaps, of slightly less rugged mechanical construction. Among the three companies, Tamron historically has produced the best macro lenses.
Exposure
Unless you are using close-up lenses, when doing any kind of macro work, you always have to consider the effective f-stop. Even if you are using the SLR body's built-in meter, which will correct automatically for light loss, you can't turn off your brain. Why not? Because the effective aperture affects picture quality.
Taking pictures through a pinhole results in tremendous depth of field but very low sharpness due to diffraction. This is why lenses for a 35mm film camera stop at f/22 and don't go to f/45 or f/64. Large format camera lenses provide these smaller apertures for two reasons: (1) the lenses are longer (f/64 on a 210mm lens is not all that small a hole); (2) the negative won't be enlarged very much.
If you're at 1:1 and have selected f/22 on the macro lens barrel, you need to look at the lens markings and/or the close-up exposure dial in the Kodak Professional Photoguide to learn that your effective aperture is f/45.
If you're using a handheld meter, you absolutely must use these corrections (e.g., meter says f/22 but you're focussed down to 1:1 so you set f/11 on the lens barrel).
[Note: Nikon bodies show you the effective aperture in the viewfinder, a really great feature for macro use; Canon EOS cameras do not.]
Lighting
A good quick and dirty lighting technique is to use a through-the-lens (TTL) metered flash with a dedicated extension cord (Nikon SC 29 off-camera flash cord or Canon Off Camera Shoe Cord 2). A modern handheld flash is extremely powerful when used a few inches from a macro subject. That lets you stop down to f/16 and smaller for good depth of field. You can hold the flash to one side of the subject and have an assistant hold a white piece of paper on the other side to serve as a reflector. If you want a softer light, you will have enough power in the flash to use almost any kind of diffusion material. The TTL meter in the camera will turn the flash off when enough light has reached the sensor.
Lighting is the most important and creative part of any kind of photography. We have an entire book chapter on the subject that might be worth reading.
The Samoyed nose at right belongs to Alex, captured with a Canon EOS-5, 180/2.8 macro lens, and TTL-metered Canon flash. Below: a foot recently pulled out of one of those weird sandals with all the bumps. Nikon 8008, 60/2.8 lens, SB-24 lens with SC-17 cord
Let's combine what we've learned until now: the aquarium
Combining everything we've learned up to this point, let's look at a case study: the aquarium. The items inside are pretty close, so you need a macro lens. If you put a rubber lens hood on the front of the lens, then you can mush it up against the glass and avoid reflections. Now you need light. Well, you can just get a flash on an extension cord and point it into the aquarium from just about anywhere.
Here are some examples from the public aquarium in Monterey, taken with a Nikon 8008, 60mm AF macro lens (set for manual focus), SB-24 flash, SC-17 extension cord. I wiped the glass with a handkerchief, asked my friend to hold the flash, and pushed the lens hood up against the glass:
People often write in wondering "How did you manage to get a lawyer in that last frame..."
Focus
With a depth of field of around one millimeter for precise macro work, camera positioning and focus become critical. If you have a good tripod and head, you'll find that you have at least 10 controls to adjust. Each of them will move the camera. None of them will move the camera along the axis that you care about.
That's why people buy macro focusing rails, e.g., Adorama Macro Focusing Rail, $180. These are little rack and pinions capable of moving the entire camera/lens assembly forward and back. You use the tripod to roughly position the camera/lens and then the macro rail to do fine positioning.
The photos below are snapshots from the garden of the Getty Center. They were taken with a fancy Canon EF 180mm f3.5L Macro USM (review), but without a tripod. It was thus impossible to focus precisely or stop down enough to get sufficient depth of field. The results are rather disappointing...
Beyond 1:1 the Canon Way
In the Canon EOS system, going beyond 1:1 is as simple as buying Canon MP-E 65mm f/2.8 1-5X Macro (review). Mount lens on tripod, mount camera on lens, twist ring on lens, release shutter:
(Flower interior at above left was captured with a traditional EOS film body; the jelly bean image at above right was taken with a D30 digital body (party like it's 2001).)
Beyond 1:1 with Nikon, et al
If you don't have a Canon EOS system and the special 1-5X lens, going beyond 1:1 requires more than buying a lens and turning the focus ring.
First, you can get a bellows (flexible accordion) and/or some extension tubes. These will let you push the lens farther away from the camera body. Extension tubes are rigid and tough; they only let you separate your body and lens in fixed increments. Bellows are delicate but they let you continuously control the lens distance from the body. How much magnification this extra extension will get you depends on the focal length of the lens. If you have a 1000mm lens that already needs its nodal point 1000mm from the sensor plane to focus at infinity, then a 50mm extension tube isn't going to be worth much. However, if you have a 50mm lens, then that same 50mm extension will take you all the way to 1:1.
Second, you probably want a "reversing ring" for your lenses so that you can turn the back element of the lens toward your subject. Why? Think about the normal way you use a lens. You are taking a picture of the Statue of Liberty. The Statue of Liberty is larger than 24x36mm. So you point the front element of the lens at the statue and the back element at the (smaller) sensor. Your lens is designed to work like this, taking the large and compressing it into the small. However, if you are working at 10:1, where the tip of a pine needle is going to take up a big portion of the frame, you want the lens to take the small and expand it into the large. So you want to just flip the lens around.
Third, once you've reversed the lens, you probably want some way to retain the automatic diaphragm. You want the aperture to remain fully open until just before your exposure and then close down to the selected shooting aperture. Rollei medium-format cameras have an all-electric interface between camera and lens, so this is done with clean and reliable electric contacts. Canon EOS would work the same way except that, after more than 15 years, Canon hasn't bothered to manufacture a bellows for the EOS system. An independent company, Novoflex, does make a bellows for Canon EOS, but for most people the Canon MP-E 65mm f/2.8 1-5X Macro (review) is a better choice. Nikon has mechanically stopped-down diaphragms for backward compatibility so they give you a strange dual cable release contraption.
More: John Shaw's Close-ups in Nature .
Beyond 1:1 the Lazy Way
how to take close-up pictures of small things
macro \'mak-(.)ro-\ aj [macr-] 1: excessively developed : LARGE, THICK 2: of or involving large quantities 3: GROSS
Taking close-up pictures of small things is called "macro photography." I have no idea why. Perhaps because the small things in macro photography are generally larger than the things you are taking pictures of when doing "micro photography". If you really want to be pedantic then you should say you are doing "photomacrography". What Kind of Camera
Point and shoot digital cameras can have remarkable macro capabilities, but for best results you want a single-lens reflex camera. These allow you to attach special-purpose macro lenses and show you in a bright optical viewfinder what you will get on the sensor.
A typical setup might be a Canon Digital Rebel XTi (Black) (review) with a Canon EF-S 60mm f/2.8 Macro USM (review). This lens is designed for the small-sensor Canon cameras and gives a working distance equivalent to 100mm on a full-frame camera. The lens is specified to focus down to "1:1" or "life size". This means that the smallest object you can photograph that will extend to the corners of the final digital photo will be the same size as the sensor inside the Canon Rebel camera, 15x22mm. A professional photographer might use Canon EOS 5D (review) and a lens designed for full Canon EF 100mm f/2.8 Macro USM (review). Confusingly, this lens is also specified to focus down to "1:1", but this time the sensor is 24x36mm in size, the old 35mm film standard. So you can't take a photo of something quite as small as with the cheaper equipment.
In the film world, the 35mm camera systems had comprehensive range of macro lenses and accessories and some medium format systems, such as the Rollei 6008 would have at least a few lenses and extension tubes. Only the extremely patient ever did macro photography with a 4x5 inch view camera.
Doing it all with a Normal Lens
In the good old days a 35mm single-lens reflex camera came with a 50mm "normal" lens. These lenses were extremely light, rugged, and high quality, so naturally the consuming public abandoned them for heavy, fragile, low quality zooms. But that's another story... Anyway, suppose that you are out in the woods with your Canon EOS 5D, a full-frame camera and a 50mm normal lens, and you want to take a picture of the tip of a pine needle. [Everything in this section applies equally to using a 30mm prime lens, e.g., Sigma 30/1.4, on a small-sensor camera such as a Canon Rebel or Nikon D-series.]
First, though, you want to take a picture of the moon. That's pretty far away, so you feel comfortable setting the lens focusing helical to "infinity". The "nodal point" of the optics will now be 50 millimeters from the plane of the sensor. [Note: exposure for the moon should be roughly f/11 and 1/ISO-setting.]
The effort of setting up your tripod is so great that you become tired and fall asleep. When you wake up in the morning, there is a bear standing 10 feet away. You refocus your 50mm lens to get a picture of the grizzly. As you turn the helical from "infinity" to "10 feet", notice that the optics are racked out away from the sensor. The nodal point is a bit farther than 50 millimeters from the sensor plane. The lens is casting an image circle somewhat larger than the 24x36mm sensor. Some of the light gathered by the lens is therefore being lost but it isn't significant.
After snapping that photo of the bear, you notice that his fangs are glistening. These aren't going to appear very large in your last shot, so you move up until you are about 1.5 feet from the bear. That's about as close as the lens helical will let you focus. The nodal point is now pretty far from the lens. Extra light is spilling off to the edges of the frame , but still not far enough to require an exposure correction. The bear's face is 1.5 feet high. You've oriented the camera vertically so that the face fills the 36mm dimension. 36mm is about 1.5 inches. So that means you are working at "1:12". The subject is 12 times the size of the subject's image on the sensor.
You're losing some light, but also you notice that you don't have too much depth of field. A 50mm lens focussed down to a foot from the subject only has a depth of field of 1/16th of an inch at f/4. No problem. You haul out a big electronic flash and stop down to f/11. Now your depth of field is a whopping ... 1/2 inch.
Looking down, you become fascinated by some pattern's in the bear's claws. Each one is about 1.5 inches long. You'd like to fill the sensor's long dimension (36mm) with a claw, which means that the subject and its image will be the same size. You want to work at "1:1". But the folks at the lens factory skimped on the helical. You can't rack your optics out far enough to focus at 1:1. It looks like that pine needle tip photo is completely out of the question.
Why did Canon limit your ability to focus close? For starters, at 1:1 the lens would be so far away from the sensor that it would cast a huge image circle. The standard 24x36mm frame would only be a tiny fraction. So only about 1/4 of the light gathered by the lens would reach the film, i.e., you'd have a two f-stop underexposure if you used the same exposure setting that you'd used for the picture of the bear when he was 10' away. A scene that required a lens setting of f/16 at infinity would require a lens setting of about f/8 at 1:1. All this other light would be bouncing around inside your camera and lens, reducing contrast. Finally, a fixed stack of optical elements can't be designed to form sharp images at so many different focussed distances.
Close-Up Lenses
Your eyes don't focus so great on really small things either. Do you try to pull your cornea a foot away from your retina? No. You stick a magnifying glass in front of your cornea. You can do the same thing for your normal lens. Unlike your cornea, it even has convenient threads for attaching a magnifying glass. The magnifying glass screws into the same place where a filter would go.
A camera store could never sell you a "magnifying glass" for $50 so they call these things "supplementary lenses" or "close-up lenses". Good things about close-up lenses:
- they don't require any exposure corrections
- you can throw a couple in your pocket in case you need them
- they aren't very high quality though they might be good enough if you stop down to f/16 and if you can find two-element close-up lenses (e.g., Nikon-brand) instead of the cheapo one-element ones.
- you have to take them on and off constantly if you are taking pictures of things at different distances.
At right: a model of Sacre Coeur, captured with a Minolta 50mm lens and single-element Minolta-brand close-up lens. Perhaps not the world's best image, but keep in mind that the photographer was 11 years old at the time of exposure.
Macro Zoom Lenses
Macro zoom lenses are not macro lenses. They don't allow significantly greater magnification than a 30mm or 50mm normal lens and they deliver low quality.
Macro Lenses
What you want is a macro lens. Fortunately, it is difficult to buy a bad macro lens. This is kind of odd in a world where 90 percent of the lenses sold are bad. Perhaps it is because anyone in the market for a macro lens is already fairly sophisticated and quality-conscious. Partly it is because it is easier to make a single focal-length lens than a zoom.
The best macro lenses are the latest autofocus mount models made by Canon and Nikon, typically in focal lengths ranging from 50 to 200mm. Each lens will focus continuously from infinity to 1:1. You can shoot the moon and capture the bear claw without stopping to change lenses or screw in filters. How do these lenses work? Do they just have a much longer helical than the 50mm normal lens? Yes and no.
Yes a macro lens helical has much more travel than a normal lens helical. You can watch the front element move an inch or two. However, these helicals aren't just pushing a stack of glass back and forth like the 50mm's helical. Inside one of the elements is moving ("floating") so that the optical design changes to a more appropriate one for close-up photography. Thus you get sharp images at all focussed distances.
How do you choose a focal length? The same way you do with a non-macro lens. If you can't get very close to your subject at a soccer game, you don't pull out a normal lens; you bring out a 300mm telephoto lens. If you can't get close to an insect without it getting scared and flying away, then you want the 200mm lens and not the 50. If you want to compress features in a woman's face, you use a 105mm lens rather than a short wide angle lens. It is the same with macro work; longer lenses give you a flatter perspective.
At right is an image (from my Christina page) taken with an older design Canon EF 50mm f/2.5 Macro, $265. This lens incorporates a floating element for high image quality, but only goes to 1:2 without a "life size converter" (sort of like a telextender) that you stick between the lens and the camera. The 50 is also annoying because it has the ancient non-USM Canon motor. So it can't do simultaneous AF and MF like the ring-USM lenses.
Check the Canon and Nikon system pages for a current list of all the macro lenses made by those companies for their bodies.
Sigma, Tamron, and Tokina make excellent single focal length (prime) macro lenses. If you're using a system other than Canon or Nikon, these may be better quality than your own manufacturer's lens. If you're using Canon or Nikon, you might be able to save a few dollars, at the expense, perhaps, of slightly less rugged mechanical construction. Among the three companies, Tamron historically has produced the best macro lenses.
If you feel like spending a lot of money then what you want is a 6x6 cm Rollei 6008 and digital back. The Schneider 150 is probably the best macro lens available for the Rollei (only $3425), though if you're using a digital back with less than a 60mm sensor size, the Schneider 90mm macro ($3900) might work nicely. Unless you are using close-up lenses, when doing any kind of macro work, you always have to consider the effective f-stop. Even if you are using the SLR body's built-in meter, which will correct automatically for light loss, you can't turn off your brain. Why not? Because the effective aperture affects picture quality.
Taking pictures through a pinhole results in tremendous depth of field but very low sharpness due to diffraction. This is why lenses for a 35mm film camera stop at f/22 and don't go to f/45 or f/64. Large format camera lenses provide these smaller apertures for two reasons: (1) the lenses are longer (f/64 on a 210mm lens is not all that small a hole); (2) the negative won't be enlarged very much.
If you're at 1:1 and have selected f/22 on the macro lens barrel, you need to look at the lens markings and/or the close-up exposure dial in the Kodak Professional Photoguide to learn that your effective aperture is f/45.
If you're using a handheld meter, you absolutely must use these corrections (e.g., meter says f/22 but you're focussed down to 1:1 so you set f/11 on the lens barrel).
[Note: Nikon bodies show you the effective aperture in the viewfinder, a really great feature for macro use; Canon EOS cameras do not.]
Lighting
A good quick and dirty lighting technique is to use a through-the-lens (TTL) metered flash with a dedicated extension cord (Nikon SC 29 off-camera flash cord or Canon Off Camera Shoe Cord 2). A modern handheld flash is extremely powerful when used a few inches from a macro subject. That lets you stop down to f/16 and smaller for good depth of field. You can hold the flash to one side of the subject and have an assistant hold a white piece of paper on the other side to serve as a reflector. If you want a softer light, you will have enough power in the flash to use almost any kind of diffusion material. The TTL meter in the camera will turn the flash off when enough light has reached the sensor.
Lighting is the most important and creative part of any kind of photography. We have an entire book chapter on the subject that might be worth reading.
The Samoyed nose at right belongs to Alex, captured with a Canon EOS-5, 180/2.8 macro lens, and TTL-metered Canon flash. Below: a foot recently pulled out of one of those weird sandals with all the bumps. Nikon 8008, 60/2.8 lens, SB-24 lens with SC-17 cord
Let's combine what we've learned until now: the aquarium
Combining everything we've learned up to this point, let's look at a case study: the aquarium. The items inside are pretty close, so you need a macro lens. If you put a rubber lens hood on the front of the lens, then you can mush it up against the glass and avoid reflections. Now you need light. Well, you can just get a flash on an extension cord and point it into the aquarium from just about anywhere.
Here are some examples from the public aquarium in Monterey, taken with a Nikon 8008, 60mm AF macro lens (set for manual focus), SB-24 flash, SC-17 extension cord. I wiped the glass with a handkerchief, asked my friend to hold the flash, and pushed the lens hood up against the glass:
People often write in wondering "How did you manage to get a lawyer in that last frame..."
Focus
With a depth of field of around one millimeter for precise macro work, camera positioning and focus become critical. If you have a good tripod and head, you'll find that you have at least 10 controls to adjust. Each of them will move the camera. None of them will move the camera along the axis that you care about.
That's why people buy macro focusing rails, e.g., Adorama Macro Focusing Rail, $180. These are little rack and pinions capable of moving the entire camera/lens assembly forward and back. You use the tripod to roughly position the camera/lens and then the macro rail to do fine positioning.
The photos below are snapshots from the garden of the Getty Center. They were taken with a fancy Canon EF 180mm f3.5L Macro USM (review), but without a tripod. It was thus impossible to focus precisely or stop down enough to get sufficient depth of field. The results are rather disappointing...
Beyond 1:1 the Canon Way
In the Canon EOS system, going beyond 1:1 is as simple as buying Canon MP-E 65mm f/2.8 1-5X Macro (review). Mount lens on tripod, mount camera on lens, twist ring on lens, release shutter:
(Flower interior at above left was captured with a traditional EOS film body; the jelly bean image at above right was taken with a D30 digital body (party like it's 2001).)
Beyond 1:1 with Nikon, et al
If you don't have a Canon EOS system and the special 1-5X lens, going beyond 1:1 requires more than buying a lens and turning the focus ring.
First, you can get a bellows (flexible accordion) and/or some extension tubes. These will let you push the lens farther away from the camera body. Extension tubes are rigid and tough; they only let you separate your body and lens in fixed increments. Bellows are delicate but they let you continuously control the lens distance from the body. How much magnification this extra extension will get you depends on the focal length of the lens. If you have a 1000mm lens that already needs its nodal point 1000mm from the sensor plane to focus at infinity, then a 50mm extension tube isn't going to be worth much. However, if you have a 50mm lens, then that same 50mm extension will take you all the way to 1:1.
Second, you probably want a "reversing ring" for your lenses so that you can turn the back element of the lens toward your subject. Why? Think about the normal way you use a lens. You are taking a picture of the Statue of Liberty. The Statue of Liberty is larger than 24x36mm. So you point the front element of the lens at the statue and the back element at the (smaller) sensor. Your lens is designed to work like this, taking the large and compressing it into the small. However, if you are working at 10:1, where the tip of a pine needle is going to take up a big portion of the frame, you want the lens to take the small and expand it into the large. So you want to just flip the lens around.
Third, once you've reversed the lens, you probably want some way to retain the automatic diaphragm. You want the aperture to remain fully open until just before your exposure and then close down to the selected shooting aperture. Rollei medium-format cameras have an all-electric interface between camera and lens, so this is done with clean and reliable electric contacts. Canon EOS would work the same way except that, after more than 15 years, Canon hasn't bothered to manufacture a bellows for the EOS system. An independent company, Novoflex, does make a bellows for Canon EOS, but for most people the Canon MP-E 65mm f/2.8 1-5X Macro (review) is a better choice. Nikon has mechanically stopped-down diaphragms for backward compatibility so they give you a strange dual cable release contraption.
More: John Shaw's Close-ups in Nature .
Beyond 1:1 the Lazy Way
| At left are a couple of Ant Robots built at the MIT AI Lab by James McLurkin. Photographed with Canon EOS-5 and Canon 50/2.8 macro lens (lit by off-camera 430 EZ flash). This lens only goes to 1:2. At right is a detail of the ant claws, which was taken with the Raynox Micro-Explorer. The Raynox is a set of close-up lenses, 6X, 12X, and 24X. These images are the result of mounting the 6X lens on a Canon 35-350L zoom lens. | |
| Here is the original ant claw picture. You can see that vignetting was severe at f/16. Fortunately, this was apparent in the viewfinder with the depth-of-field preview button pressed, so the composition was made with an eye toward eventual cropping. Vignetting is the principal drawback of the MicroExplorer and it is apparently worse at small apertures. |
| A couple more example MicroExplorer shots (at left is an Ant robot detail; at right is a quarter on a $20 bill, full frame at f/8 (I think)). Note that vignetting is not as severe as it was at f/16 (above left). |
As there is no one cameras that can fulfill all type of shooting situation, same goes to camera lenses. Each camera lens has its own characteristics and element with distinct advantage and disadvantage over others. By learning more about how camera lenses
As there is no one cameras that can fulfill all type of shooting situation, same goes to camera lenses. Each camera lens has its own characteristics and element with distinct advantage and disadvantage over others. By learning more about how camera lenses differentiate over each other, we get to know how to apply the right camera lens according the situation and demands.
It used to be that most 35mm SLR cameras (equivalent to the full frame format for Digital SLR) in the market come together with a 'standard lens'. Standard lens here refer to a lens with focal length of 50mm and this is the format that most people regards roughly as what we normally see with our own eye. As such, 50mm is still a very popular lens among all photographers. Normally 50mm camera lens has a maximum aperture of f1.8. There are also faster lens with maximum aperture of f1.4 and even f1.2. These fast lenses prove to bring better quality and much more useful though it all comes with much expensive price.
A thing that must take note of is that all SLR/DSLR cameras have interchangeable lenses. Changing of lenses can be done easily and is differentiated by the mount of the camera. The most popular mount for most cameras used today is the bayonet mount. In order to change lens in a bayonet mount, for taking out lens, press on a switch nearby to the mount then simply turn the lens 45 degree in a clockwise direction; for inserting another lens, simply align the lens accordingly to the marking on the camera body and camera lens and turn the lens in 45 degree anti clockwise.
The ability of changing lenses in SLR/DSLR is properly one of the biggest reasons behind the creativity and vast usability in photography compare to other cameras. Thus, a camera with a standard lens would not be able to allow you in using the camera to its fullest. Generally, most photographers will consider getting or must get another two lenses in the category of wide angle lens and telephoto lens.
What is wide angle lens? Wide angle lens usually cover in the focal range of 28mm to 35mm for full frame format. It will generally provide a wide angle view of what you see. As more area in front of the camera will be captured into the photo, it is widely use in landscape photography. Using wide angle lens, photographers generally has better control over the composition of the photo as the photographed subject can be really near to the photographer while at the same time the background can be kept in focus.
On the other hand, a medium telephoto lens usually covers the focal range of 85mm to 135mm. It generally gives photographer an advantage of capturing a subject that is far away. And more importantly, it is a superb portrait lens. Wide angle lens tends to makes the photo of a person's face appear bulbous due to the focal range; with telephoto lens, a portrait photo captured with the focal range of probably around 100m will result in the photos to appear more pleasing. As the photographer would have to be quite a distance away, the person being photographed tends to be more relaxed and the end result photos will appear much natural as well. Other than that, a telephoto lens tends to make the background in the photo to appear much out of focus. While it is used in portrait photography, this will brings out more of the photographed subject, his/her eye, face, etc which will greatly enhance the photo.
In between wide angle and telephoto lens, many photographers have their preference on zoom lens as it is very convenient. Zoom lens as what it has in its name provides photographers the luxury of adjusting the focal lengths easily without changing the lens between wide angle and telephoto. Of course, the disadvantage of zoom lens is it would not be able to provide the level of quality a prime lens would provide. Though with the technology for the camera lens nowadays, it will take a really detail eye to notice the difference.
Other than these, there are also few types of special lens for specific purpose. For example, fisheye lens and macro lens. The macro lens will allows the photographer to take photo of subject appearing in life size while fish eye lens will provide a visual of 360 degree surrounding, as mimic to how fish is looking to the world. Such special lens can produce really dramatic result though it is not really any everyday use equipment as compare to the typical wide angle and telephoto lenses.
Find out more things about camera lenses. Know more about camera lenses and how to use it to its full potential. Check out Basic Camera Photography for more information.
Bracketing Exposures
Bracketing Exposures
Most modern DSLR cameras and some top end compact cameras have the facility to set up a series of shots taken at different exposures, this is called bracketing. In the diagram on the right you can see the display from my Canon 7D set to take three different exposures, one at the correct exposure according to the meter reading, one at one f-stop under and one at one f-stop over. These settings will apply to the next three shots I take. The first shot will be the 'correct' exposure, followed by the under exposure and lastly the over exposure.
Use Bracketing in conjunction with the high speed drive mode.
Whilst 'auto bracketing' remains set (until I cancel it) the camera will cycle through the same three exposure settings so, if my 'drive' is set to single shot, I must remember to take three shots of each scene. However, if I set the 'drive' to 'continuous shooting' mode, it will take three shots (at the different exposures) and stop. This seems a much better way to work, especially on the high speed drive setting, I can take three exposures in rapid succession, so the shots will be almost identical and I don't have to remember how many shots I have taken.
When to bracket exposures
Bracketing is very useful when the lighting is difficult, the background keeps changing or there is too much contrast. You then have a set of pictures to choose from when you get home. You can even choose bits from different pictures if you are a keen Photoshopper.
When you are photographing a nice peaceful landscape you have time to study the pictures and, more importantly, the histograms, and take another shot if necessary. Conversely, when you are shooting sports, there is no time for bracketing as every second, or even fraction of a second, counts (The observant among you will have noticed that I could not possibly have used bracketing on the shots on the left as there is no difference between them. I 'faked' the differences in Adobe Camera Raw just to show the type of effect you get from bracketing). However, when you are taking pictures of people or things moving at normal speed, pictures of the kids playing for instance, then bracketing with a fast 'drive' is not a bad idea.
I have many otherwise good photos that have been spoiled by a burnt out highlight on the face. These would have benefited from a shorter exposure. Likewise I have pictures that came out too dark and, although they can be saved to some extent by careful editing, they lack the range of tones you would get in a properly exposed photo.
How wide should the bracket be?
In the old days of film, the rule of thumb was that, if you were using negative film, a whole f-stop between exposures would be OK. If you were using slide film 1/2 stop or 1/3 stop increments would be better.
The same really applies with digital exposures, if you are shooting RAW then one stop would be a good gap. If you are shooting jpegs then you need to make the gap between exposures closer as there is less opportunity to correct problems in post processing. If you look at the diagram at the top of the page you will see that I have set the gap at one f-stop as I always shoot RAW files.
Using bracketing and Exposure compensation together
The center of the bracket does not necessarily have to be in the middle of the exposure dial. It is possible to apply exposure compensation and add bracketing at the same time.
So you could have the 'over exposure' on the center line of the scale. This would give you a 'correct' exposure, one stop under and two stops under. Or you could set the 'under exposure' on the center line and have one stop and two stops over.
The latter would have been the way to go for the picture above as the 'correct' exposure according to the meter produced the top frame. As I said in my article on photographing in the snow, all skiing shots should be over exposed by at least one stop because of the light background. Here, although we are not photographing against the snow, the sun is behind the subject fooling the meter into under exposing the shot.
So, although automatic metering is very good in most circumstances, you can see here a couple of ways that it can easily be fooled. If you are in any doubt as to whether the camera will produce the best possible exposure, try bracketing to give you
Most modern DSLR cameras and some top end compact cameras have the facility to set up a series of shots taken at different exposures, this is called bracketing. In the diagram on the right you can see the display from my Canon 7D set to take three different exposures, one at the correct exposure according to the meter reading, one at one f-stop under and one at one f-stop over. These settings will apply to the next three shots I take. The first shot will be the 'correct' exposure, followed by the under exposure and lastly the over exposure.
Use Bracketing in conjunction with the high speed drive mode.
Whilst 'auto bracketing' remains set (until I cancel it) the camera will cycle through the same three exposure settings so, if my 'drive' is set to single shot, I must remember to take three shots of each scene. However, if I set the 'drive' to 'continuous shooting' mode, it will take three shots (at the different exposures) and stop. This seems a much better way to work, especially on the high speed drive setting, I can take three exposures in rapid succession, so the shots will be almost identical and I don't have to remember how many shots I have taken.
When to bracket exposures
Bracketing is very useful when the lighting is difficult, the background keeps changing or there is too much contrast. You then have a set of pictures to choose from when you get home. You can even choose bits from different pictures if you are a keen Photoshopper.
When you are photographing a nice peaceful landscape you have time to study the pictures and, more importantly, the histograms, and take another shot if necessary. Conversely, when you are shooting sports, there is no time for bracketing as every second, or even fraction of a second, counts (The observant among you will have noticed that I could not possibly have used bracketing on the shots on the left as there is no difference between them. I 'faked' the differences in Adobe Camera Raw just to show the type of effect you get from bracketing). However, when you are taking pictures of people or things moving at normal speed, pictures of the kids playing for instance, then bracketing with a fast 'drive' is not a bad idea.
I have many otherwise good photos that have been spoiled by a burnt out highlight on the face. These would have benefited from a shorter exposure. Likewise I have pictures that came out too dark and, although they can be saved to some extent by careful editing, they lack the range of tones you would get in a properly exposed photo.
How wide should the bracket be?
In the old days of film, the rule of thumb was that, if you were using negative film, a whole f-stop between exposures would be OK. If you were using slide film 1/2 stop or 1/3 stop increments would be better.
The same really applies with digital exposures, if you are shooting RAW then one stop would be a good gap. If you are shooting jpegs then you need to make the gap between exposures closer as there is less opportunity to correct problems in post processing. If you look at the diagram at the top of the page you will see that I have set the gap at one f-stop as I always shoot RAW files.
Using bracketing and Exposure compensation together
The center of the bracket does not necessarily have to be in the middle of the exposure dial. It is possible to apply exposure compensation and add bracketing at the same time.
So you could have the 'over exposure' on the center line of the scale. This would give you a 'correct' exposure, one stop under and two stops under. Or you could set the 'under exposure' on the center line and have one stop and two stops over.
The latter would have been the way to go for the picture above as the 'correct' exposure according to the meter produced the top frame. As I said in my article on photographing in the snow, all skiing shots should be over exposed by at least one stop because of the light background. Here, although we are not photographing against the snow, the sun is behind the subject fooling the meter into under exposing the shot.
So, although automatic metering is very good in most circumstances, you can see here a couple of ways that it can easily be fooled. If you are in any doubt as to whether the camera will produce the best possible exposure, try bracketing to give you
Exposure
Exposure
How to get a photo correctly exposed by adjusting aperture and shutter speed
Many people let their cameras determine exposure for them. They leave the camera on its manual setting, and hope that the camera gets everything right. There is only one problem.
If you let your camera determine exposure for you, it won't always get it right. The camera thinks that everything in a photograph should show up as a medium tone. Take a photo of a white wall and it will wind up looking grey — the camera has intentionally underexposed the image. Take a photo of a black wall and it will also look grey — the camera has overexposed the image.
How Aperture and Shutter Speed Determine Exposure
Quick review: aperture is primarily used to change the depth of field, and shutter speed is used to blur or freeze motion.
Aperture is also a measure of how wide the lens opens when you take a photo. Shutter speed is how long the shutter stays open. Both of these settings affect the amount of light hitting the camera's image sensor, and this is what determines exposure.
When the correct amount of light hits the image sensor of your camera, you get a photograph that is correctly exposed. When there is not enough light, the image is underexposed and when there is too much light, the image is overexposed.
The relationship between aperture and the amount of light that gets into the camera is a little backwards:
SMALL F-STOP NUMBER = LOTS OF LIGHT
LARGE F-STOP NUMBER = MINIMAL LIGHT
Here is an example of how this works with actual f-stop numbers:
f4.5 (wide open) = LARGE AMOUNT OF LIGHT
f8.0 (somewhat open) = MEDIUM AMOUNT OF LIGHT
f22 (almost closed) = SMALL AMOUNT OF LIGHT
The important point here is that if you have your aperture set to a small number (ignoring shutter speed for now) a lot of light is going to get into the camera. When you are shooting in low-light conditions (at dusk, for example) you will have no choice but to set the aperture wide open to capture as much light as possible.
When you are shooting in bright conditions, you have more flexiblity to change the aperture (since you can let in less light and still get a good photograph). You can set the aperture to a high number and let in less light as a result.
We've covered aperture and the amount of light let into the camera. Here is the relationship between shutter speed and amount of light:
SLOW SHUTTER SPEED = LARGE AMOUNT OF LIGHT
FAST SHUTTER SPEED = SMALL AMOUNT OF LIGHT
Again, let's say that you are only adjusting your shutter speed and ignoring aperture. In low-light conditions, you will have to use a slower shutter speed to capture enough light for a good exposure. In bright conditions, you can use a range of shutter speeds, but may not be able to use slow shutter speeds since this will let in too much light.
So far, we have just gone over changing either the aperture or the shutter speed and not worrying about the other. Well, the truth is that you can manipulate both to achieve a correct exposure.
The following table shows this relationship (assuming that you are taking a standard photo during the day).
Light Sensors and The Middle of the Road
Film and digital camera light sensors are always trying to get a correct exposure. If you don't change anything, point the camera at a scene and take the shot, chances are the camera will get the exposure correct automatically. So why ever fuss with it?
Your camera's light sensor can be fooled.
Say that you are taking a photo of some mountains with a bright blue sky in the background. You take the photograph on automatic. When you look at the photo later, the mountain looks just fine, but the sky is pure white, not blue. Why?
Your camera's light sensor wanted to make sure that everything in the photograph was correctly exposed. In order to correctly expose the mountain, it overexposed the sky.
Here is another example: you take a photo of your friend standing in front of a bright background. When the photo turns out, the background looks just fine, but your friend's face is completely dark. In order to correctly expose the background, the camera underexposed your friend.
If you want to prevent this from happening, you have to override your camera's automatic features and adjust the aperture and shutter speed yourself.
Don't Trust Your Eyes
Another problem with exposure is that cameras cannot capture the same range of light and shadow that our eyes can. You may be standing in the middle of the forest on a path with beams of light breaking through the trees and think that you can get a beautiful photograph.
The trick here is that your eyes see all of the detail in the shadows, despite the rays of light beaming through. If you try to take a photograph of this scene, one of two things is going to happen: you will either expose correctly for the shadows (which makes the beams of light pure white with no detail) or you will expose for the light (making the trees completely black with no detail).
Sometimes you have to realize that something that looks remarkable to your eyes cannot be captured with your camera no matter how much you fuss with the exposure.
How to get a photo correctly exposed by adjusting aperture and shutter speed
Many people let their cameras determine exposure for them. They leave the camera on its manual setting, and hope that the camera gets everything right. There is only one problem.
If you let your camera determine exposure for you, it won't always get it right. The camera thinks that everything in a photograph should show up as a medium tone. Take a photo of a white wall and it will wind up looking grey — the camera has intentionally underexposed the image. Take a photo of a black wall and it will also look grey — the camera has overexposed the image.
How Aperture and Shutter Speed Determine Exposure
Quick review: aperture is primarily used to change the depth of field, and shutter speed is used to blur or freeze motion.
Aperture is also a measure of how wide the lens opens when you take a photo. Shutter speed is how long the shutter stays open. Both of these settings affect the amount of light hitting the camera's image sensor, and this is what determines exposure.
When the correct amount of light hits the image sensor of your camera, you get a photograph that is correctly exposed. When there is not enough light, the image is underexposed and when there is too much light, the image is overexposed.
The relationship between aperture and the amount of light that gets into the camera is a little backwards:
SMALL F-STOP NUMBER = LOTS OF LIGHT
LARGE F-STOP NUMBER = MINIMAL LIGHT
Here is an example of how this works with actual f-stop numbers:
f4.5 (wide open) = LARGE AMOUNT OF LIGHT
f8.0 (somewhat open) = MEDIUM AMOUNT OF LIGHT
f22 (almost closed) = SMALL AMOUNT OF LIGHT
The important point here is that if you have your aperture set to a small number (ignoring shutter speed for now) a lot of light is going to get into the camera. When you are shooting in low-light conditions (at dusk, for example) you will have no choice but to set the aperture wide open to capture as much light as possible.
When you are shooting in bright conditions, you have more flexiblity to change the aperture (since you can let in less light and still get a good photograph). You can set the aperture to a high number and let in less light as a result.
We've covered aperture and the amount of light let into the camera. Here is the relationship between shutter speed and amount of light:
SLOW SHUTTER SPEED = LARGE AMOUNT OF LIGHT
FAST SHUTTER SPEED = SMALL AMOUNT OF LIGHT
Again, let's say that you are only adjusting your shutter speed and ignoring aperture. In low-light conditions, you will have to use a slower shutter speed to capture enough light for a good exposure. In bright conditions, you can use a range of shutter speeds, but may not be able to use slow shutter speeds since this will let in too much light.
So far, we have just gone over changing either the aperture or the shutter speed and not worrying about the other. Well, the truth is that you can manipulate both to achieve a correct exposure.
The following table shows this relationship (assuming that you are taking a standard photo during the day).
| Aperture | Shutter Speed | |
| Slow (1/30 sec) | Fast (1/1000 sec) | |
| Small f-stop (f4.5) | Overexposed — a slow shutter speed and small f-stop will both let in more light | Correct — a fast shutter speed lets in less light, but a small f-stop lets in more |
| Large f-stop (f22) | Correct — a slow shutter speed lets in more light, but a large f-stop lets in less | Underexposed — a fast shutter speed and large f-stop both let in less light |
Film and digital camera light sensors are always trying to get a correct exposure. If you don't change anything, point the camera at a scene and take the shot, chances are the camera will get the exposure correct automatically. So why ever fuss with it?
Your camera's light sensor can be fooled.
Say that you are taking a photo of some mountains with a bright blue sky in the background. You take the photograph on automatic. When you look at the photo later, the mountain looks just fine, but the sky is pure white, not blue. Why?
Your camera's light sensor wanted to make sure that everything in the photograph was correctly exposed. In order to correctly expose the mountain, it overexposed the sky.
Here is another example: you take a photo of your friend standing in front of a bright background. When the photo turns out, the background looks just fine, but your friend's face is completely dark. In order to correctly expose the background, the camera underexposed your friend.
If you want to prevent this from happening, you have to override your camera's automatic features and adjust the aperture and shutter speed yourself.
Don't Trust Your Eyes
Another problem with exposure is that cameras cannot capture the same range of light and shadow that our eyes can. You may be standing in the middle of the forest on a path with beams of light breaking through the trees and think that you can get a beautiful photograph.
The trick here is that your eyes see all of the detail in the shadows, despite the rays of light beaming through. If you try to take a photograph of this scene, one of two things is going to happen: you will either expose correctly for the shadows (which makes the beams of light pure white with no detail) or you will expose for the light (making the trees completely black with no detail).
Sometimes you have to realize that something that looks remarkable to your eyes cannot be captured with your camera no matter how much you fuss with the exposure.
What Is... Aperture?
What Is... Aperture?
When you look at the technical specifications of a digital camera, one of the very first specification mentioned is its maximum aperture and/or its aperture range.
What is 'aperture,' what is a good aperture range, and how is aperture relevant when it comes to choosing a digital camera?
What Is Aperture?
The main function of a camera lens is to collect light. The aperture of a lens is the diameter of the lens opening and is usually controlled by an iris. The larger the diameter of the aperture, the more light reaches the film / image sensor.
Aperture is expressed as F-stop, e.g. F2.8 or f/2.8. The smaller the F-stop number (or f/value), the larger the lens opening (aperture).
[Note: Many camera user manuals today will refer to the aperture in terms of "aperture value" instead of f/value. I'm not sure when this trend started but don't get confused between "aperture" and "aperture value." Aperture value" is simply another way of saying f/value.]
In practice, unless you are dealing with a fixed-aperture lens (many simple point-and-shoot cameras have only one fixed aperture), the aperture of a lens is usually expressed as a range of fstops.
When you read the specifications of a camera, the aperture may be expressed in a number of different ways, the following three being the most common:
A "fast" lens is one that has a large maximum aperture (F2.4, F2.0 for current digital cameras; F1.4, F1.2 for 35mm film cameras).
Quick Quiz: which lens has a larger opening (aperture): one with an aperture of F1.8 or one with an aperture of F2.8?
Answer: F1.8 (remember, the smaller the F-stop, the larger the aperture)
A Good Aperture Range
My personal preference for a 'good' aperture range is:
F1.8 - F16
This tells us that the camera has an aperture range of F1.8 to F16; the maximum aperture is F1.8, and the minimum aperture is F16.
There are 5 f-stops between the max and min aperture. If your camera's lens is currently set at an aperture of F5.6, closing it by 1 f-stop would mean selecting F8; opening it up by 1 f-stop would mean selecting F4.
How Is A Large Maximum Aperture Relevant?
A large maximum aperture is preferable to a smaller one since it gives the photographer more latitude in the kind of pictures that can be taken.
For example, it is pretty obvious that the larger the aperture, the better your digital camera will perform in low-light situations, since a larger lens opening is able to admit more light than a smaller lens opening.
A larger max. aperture also allows you to use a faster shutter speed to freeze action.
So, let's say the light meter in your digital camera calculates that for proper exposure in that indoor arena, you need an aperture of F4 and a shutter speed of 1/60 sec.
To use a faster shutter speed (say, 1/250 sec.) to freeze action, you have to open up the aperture to allow more light in for that shorter amount of time.
For every shutter speed increment we go up, we need to open up a f-stop of aperture. From 1/60 sec. to 1/250 sec. there are 2 increments, so we open up the aperture by 2 f-stops, going from F4 to F1.8. Note that the camera would give proper exposure at 1/60 sec. at F4, 1/125 sec. at F2.8, and 1/250 sec. at F1.8, since all three aperture/shutter speed combinations allow the same amount of light into the camera. [Some digital cameras provide a 'Program Shift' function to allow that very shifting of aperture/shutter speed combinations in tandem.]
Of course, in a digital camera set on Auto mode, you can select Sports scene mode, and the camera will automotically select a fast shutter speed and the appropriate aperture. Likewise, in Shutter-Priority mode, you can choose which shutter speed you want (fast or slow), and the camera will select the appropriate aperture for proper exposure.
In our example above, let's say the lens on your digital camera only opens up to a max. aperture of F2.8. If you now select 1/250 sec. (in Shutter-Priority mode), the camera will not be able to select an aperture larger than F2.8 (in our example, it really needs F1.8). It would then give you an "underexposure" warning. If you go ahead and take the picture anyway, your picture would be 1 f-stop underexposed (i.e. you really needed to open up the aperture by 1 more f-stop for correct exposure).
Similarly, if you select a shutter speed of 1/4 sec. and the lens only closes down to a min. aperture of F8 (in our example, it really needs F16), the camera would give you an "overexposure" warning. If you go ahead and take a picture anyway, your picture would be 2 f-stops overexposed (i.e. you really needed to close down the aperture by 2 more f-stops for correct exposure).
[Editor's note: There is a third variable in the above example which we have purposefully not introduced. This is the sensitivity of the image sensor -- the ISO. We'll cover this in a later tutorial.]
How Is A Small Minimum Aperture Relevant?
A small minimum aperture is preferable to a larger one since it also gives the photographer more latitude in the kind of pictures that can be taken.
Suppose we want to take a picture of flowing water. As mentioned above, to depict flowing water, we usually want to use a slow shutter speed so that the water blurs. It is this blurring that makes the picture so effective in depicting water motion.
So, let's say the light meter in your digital camera calculates that for proper exposure on a bright sunny day, you need an aperture of F8 and a shutter speed of 1/125 sec.
Well, if you decide to use a slower shutter speed (say, 1/30 sec.), this means that you have to compensate by closing down the aperture to allow less light in.
It makes sense really. Since you have increased the time the shutter remains open to allow light in, you must compensate by allowing less light in to expose the image sensor in that longer amount of time, if you still want a properly exposed picture.
But, what if the lens on your digital camera closes to a minimum of F8? You're stuck at the shutter speed of 1/125 sec. If you use 1/30 sec. at F8, your picture will be overexposed, i.e. burnt out. At 1/125 sec. and F8, your picture will be properly exposed but the fast shutter speed will freeze the water motion and you won't obtain the blurring effect you desire.
If the lens in your digital camera closed down to F16, presto, your problem is solved! 1/125 sec. at F8 is equivalent to 1/30 sec. at F16, which means that you would have a perfectly exposed purposefully-blurred-for-effect flowing water shot. [If your lens does not close down to F16, you could use a Neutral Density (ND) filter to reduce the amount of light coming into the lens, and thus allowing you to use a slower shutter speed.]
[Editor's note: There is a third variable in the above example which we have purposefully not introduced. This is the sensitivity of the image sensor -- the ISO. We'll cover this in a later tutorial.]
Aperture and Depth of Field (DOF)
We mentioned this above but feel it is important enough to repeat in its own paragraph.
The Depth of Field is the distance wherein objects are in focus.
There are times when you desire a great depth of field, i.e. where objects both close to you and far from you are in focus. This is especially true when you are taking a landscape picture and want as much as possible to be in crisp focus.
Then there are times when you want to isolate your subject, as when you are taking a portrait and want your subject to be in sharp focus but the background to be out of focus. In this case, you desire a shallow depth of field.
One way to influence DOF is by selecting the appropriate aperture.
The rule of thumb is this:
Here are some real images that demonstrate the use of aperture to influence DOF:
Note: Since we are on the subject of DOF, DOF also changes with focal length. Use a small focal length to increase DOF, a longer focal length obtain a shallower DOF. I.E. if you zoom, the DOF decreases. [OK, to be technically correct, focal length does not really affect DOF, but gives the effect that it does. And, that's good enough for us since that's what we're after. We'll cover DOF in a later tutorial.]
Due to the small image sensors used, digital cameras use such small focal lengths that it is very difficult to obtain shallow depth of field even when using a large aperture. In the example above, we used a large aperture AND a long focal length (telephoto macro) to achieve a shallow DOF.
Recap
A large maximum aperture is a good thing. It allows more light to reach the image sensor, and so allows you to use a faster shutter speed. A faster shutter speed freezes action and negates the effect of camera shake, resulting in pictures that are not blurred.
Another advantage of a large maximum aperture is to provide a shallow depth of field. This allows the background to blur nicely thus isolating your subject (especially effective when taking portraits).
A small minimum aperture is also a good thing. It allows you to use a slow shutter speed on a bright sunny day. A slow shutter speed allows you to depict motion.
Another advantage of a small minimum aperture is to increase the depth-of-field. An increased depth-of-field allows you to take landscape pictures where as much of the picture in the foreground and reaching all the way to the background (usually, 'infinity') is in sharp focus.
Our Readers Write Back
We don't pretend to be experts in all aspects of digital photography and therefore are very happy to learn together with our readers. Their feedback to this article are published below.
From: Robert Counts
The only unanswered question in my mind is about the recipes given for aperture and shutter spead at the bottom section of the "Good ApetureRange" section. My question along the line of: Are these aperture recipes set? I noticed that in the set of photos below where depth of field is being illustrated, the aperture/shutter specifications are different from the ones in the diagrams above, but the photos still look good. I know that this is an answer that will come with shooting experience, which is what I need to do on my own, on top of reading tutorials like this, but that further explanation would be really helpful for us beginners. Thanks so much for making this great tutorial available!
Editor: Notice that the article talks about Good Aperture Range. We are suggesting what a good range is. There is no such thing as a 'good aperture' -- an aperture is basically just a hole that allows light in.
As far as the aperture range is concerned, a large aperture allows more light in and therefore allows us to take natural light picture (i.e. without flash) when there's not much light to go around. That's good. A large aperture also allows us to shorten the depth of field, important for occasions when we want to blur the background and have our subject stand out
in sharp contrast to the background. That is very good!
A small aperture allows us to limit the amount of light that comes into the camera and this allows us to use a slower shutter speed in bright lights for occasions when we want to depict motion, e.g. flowing water. [When it's still too bright, photographers use Neutral Density filter(s) to reduce the amount of light coming into the camera.] More importantly, a small aperture also increases depth of field and ensures that objects from near to far are all in sharp focus, as we like to have in landscapes. That is very good!
The sample images show that we can take good photos at all apertures. But a good range of apertures allow us to take more good photos, especially those that depend on depth of field
When you look at the technical specifications of a digital camera, one of the very first specification mentioned is its maximum aperture and/or its aperture range.
What is 'aperture,' what is a good aperture range, and how is aperture relevant when it comes to choosing a digital camera?
What Is Aperture?
The main function of a camera lens is to collect light. The aperture of a lens is the diameter of the lens opening and is usually controlled by an iris. The larger the diameter of the aperture, the more light reaches the film / image sensor.
Aperture is expressed as F-stop, e.g. F2.8 or f/2.8. The smaller the F-stop number (or f/value), the larger the lens opening (aperture).
[Note: Many camera user manuals today will refer to the aperture in terms of "aperture value" instead of f/value. I'm not sure when this trend started but don't get confused between "aperture" and "aperture value." Aperture value" is simply another way of saying f/value.]
In practice, unless you are dealing with a fixed-aperture lens (many simple point-and-shoot cameras have only one fixed aperture), the aperture of a lens is usually expressed as a range of fstops.
When you read the specifications of a camera, the aperture may be expressed in a number of different ways, the following three being the most common:
- Maximum Aperture:
Max. Aperture | F2.8 |
This simply states that the maximum aperture for the lens is F2.8.
- Aperture Range:
Aperture Range | F2.8-F8.0 |
This states the max. and min. aperture, the assumption being that there are standard increments between them.
- Maximum Wide-Angle and Telephoto Apertures:
Aperture | F2.8-3.5 or F2.8(W)-F3.5(T) |
This gives the max. aperture for the wide-angle (F2.8) and telephoto (F3.5) focal lengths of a zoom lens.
It is usually not too difficult to figure out that a stated range deals with maximum apertures and not max and min apertures: the mimimum aperture should be quite small at F8, F11, F16 or F22.A "fast" lens is one that has a large maximum aperture (F2.4, F2.0 for current digital cameras; F1.4, F1.2 for 35mm film cameras).
Quick Quiz: which lens has a larger opening (aperture): one with an aperture of F1.8 or one with an aperture of F2.8?
Answer: F1.8 (remember, the smaller the F-stop, the larger the aperture)
A Good Aperture Range
My personal preference for a 'good' aperture range is:
F1.8 - F16
| F1.8 | F2.8 | F4 | F5.6 | F8 | F11 | F16 |
There are 5 f-stops between the max and min aperture. If your camera's lens is currently set at an aperture of F5.6, closing it by 1 f-stop would mean selecting F8; opening it up by 1 f-stop would mean selecting F4.
| F1.8 | F2.8 | F4 | F5.6 | F8 | F11 | F16 |
A large maximum aperture is preferable to a smaller one since it gives the photographer more latitude in the kind of pictures that can be taken.
For example, it is pretty obvious that the larger the aperture, the better your digital camera will perform in low-light situations, since a larger lens opening is able to admit more light than a smaller lens opening.
A larger max. aperture also allows you to use a faster shutter speed to freeze action.
So, let's say the light meter in your digital camera calculates that for proper exposure in that indoor arena, you need an aperture of F4 and a shutter speed of 1/60 sec.
| F4 |
| 1/60 |
For every shutter speed increment we go up, we need to open up a f-stop of aperture. From 1/60 sec. to 1/250 sec. there are 2 increments, so we open up the aperture by 2 f-stops, going from F4 to F1.8. Note that the camera would give proper exposure at 1/60 sec. at F4, 1/125 sec. at F2.8, and 1/250 sec. at F1.8, since all three aperture/shutter speed combinations allow the same amount of light into the camera. [Some digital cameras provide a 'Program Shift' function to allow that very shifting of aperture/shutter speed combinations in tandem.]
| F1.8 | F2.8 | F4 | F5.6 | F8 | F11 | F16 |
| 1/250 | 1/125 | 1/60 | 1/30 | 1/15 | 1/8 | 1/4 |
In our example above, let's say the lens on your digital camera only opens up to a max. aperture of F2.8. If you now select 1/250 sec. (in Shutter-Priority mode), the camera will not be able to select an aperture larger than F2.8 (in our example, it really needs F1.8). It would then give you an "underexposure" warning. If you go ahead and take the picture anyway, your picture would be 1 f-stop underexposed (i.e. you really needed to open up the aperture by 1 more f-stop for correct exposure).
Similarly, if you select a shutter speed of 1/4 sec. and the lens only closes down to a min. aperture of F8 (in our example, it really needs F16), the camera would give you an "overexposure" warning. If you go ahead and take a picture anyway, your picture would be 2 f-stops overexposed (i.e. you really needed to close down the aperture by 2 more f-stops for correct exposure).
[Editor's note: There is a third variable in the above example which we have purposefully not introduced. This is the sensitivity of the image sensor -- the ISO. We'll cover this in a later tutorial.]
How Is A Small Minimum Aperture Relevant?
A small minimum aperture is preferable to a larger one since it also gives the photographer more latitude in the kind of pictures that can be taken.
Suppose we want to take a picture of flowing water. As mentioned above, to depict flowing water, we usually want to use a slow shutter speed so that the water blurs. It is this blurring that makes the picture so effective in depicting water motion.
So, let's say the light meter in your digital camera calculates that for proper exposure on a bright sunny day, you need an aperture of F8 and a shutter speed of 1/125 sec.
| F8 |
| 1/125 |
It makes sense really. Since you have increased the time the shutter remains open to allow light in, you must compensate by allowing less light in to expose the image sensor in that longer amount of time, if you still want a properly exposed picture.
But, what if the lens on your digital camera closes to a minimum of F8? You're stuck at the shutter speed of 1/125 sec. If you use 1/30 sec. at F8, your picture will be overexposed, i.e. burnt out. At 1/125 sec. and F8, your picture will be properly exposed but the fast shutter speed will freeze the water motion and you won't obtain the blurring effect you desire.
If the lens in your digital camera closed down to F16, presto, your problem is solved! 1/125 sec. at F8 is equivalent to 1/30 sec. at F16, which means that you would have a perfectly exposed purposefully-blurred-for-effect flowing water shot. [If your lens does not close down to F16, you could use a Neutral Density (ND) filter to reduce the amount of light coming into the lens, and thus allowing you to use a slower shutter speed.]
| F1.8 | F2.8 | F4 | F5.6 | F8 | F11 | F16 |
| 1/2,000 | 1/1,000 | 1/500 | 1/250 | 1/125 | 1/60 | 1/30 |
Aperture and Depth of Field (DOF)
We mentioned this above but feel it is important enough to repeat in its own paragraph.
The Depth of Field is the distance wherein objects are in focus.
There are times when you desire a great depth of field, i.e. where objects both close to you and far from you are in focus. This is especially true when you are taking a landscape picture and want as much as possible to be in crisp focus.
Then there are times when you want to isolate your subject, as when you are taking a portrait and want your subject to be in sharp focus but the background to be out of focus. In this case, you desire a shallow depth of field.
One way to influence DOF is by selecting the appropriate aperture.
The rule of thumb is this:
- Select a large aperture (or small f/value or small aperture value), e.g. f/2.8, to obtain a shallow DOF
- Select a small aperture (or large f/value or large aperture value), e.g. f/8.0, to achieve great DOF
Here are some real images that demonstrate the use of aperture to influence DOF:
| Aperture and Depth of Field (DOF) AF area is on yellow pistils of flower in front | |
| Shallow DOF | Great DOF |
| Note how the use of a large aperture (small aperture value) throws the flowers in the background out of focus. Focus has to be precise. | Using a small aperture (large aperture value) extends the DOF from the foreground all the way to the background. |
| 49.8 mm, Av, Spot, 1/30 sec., f/3.5, +0.7EV, Macro, Tripod used | 49.6mm, Av, Spot, 1/5 sec., f/11, +0.7EV, Macro, Tripod used |
Due to the small image sensors used, digital cameras use such small focal lengths that it is very difficult to obtain shallow depth of field even when using a large aperture. In the example above, we used a large aperture AND a long focal length (telephoto macro) to achieve a shallow DOF.
Recap
A large maximum aperture is a good thing. It allows more light to reach the image sensor, and so allows you to use a faster shutter speed. A faster shutter speed freezes action and negates the effect of camera shake, resulting in pictures that are not blurred.
Another advantage of a large maximum aperture is to provide a shallow depth of field. This allows the background to blur nicely thus isolating your subject (especially effective when taking portraits).
A small minimum aperture is also a good thing. It allows you to use a slow shutter speed on a bright sunny day. A slow shutter speed allows you to depict motion.
Another advantage of a small minimum aperture is to increase the depth-of-field. An increased depth-of-field allows you to take landscape pictures where as much of the picture in the foreground and reaching all the way to the background (usually, 'infinity') is in sharp focus.
Our Readers Write Back
We don't pretend to be experts in all aspects of digital photography and therefore are very happy to learn together with our readers. Their feedback to this article are published below.
From: Robert Counts
The only unanswered question in my mind is about the recipes given for aperture and shutter spead at the bottom section of the "Good ApetureRange" section. My question along the line of: Are these aperture recipes set? I noticed that in the set of photos below where depth of field is being illustrated, the aperture/shutter specifications are different from the ones in the diagrams above, but the photos still look good. I know that this is an answer that will come with shooting experience, which is what I need to do on my own, on top of reading tutorials like this, but that further explanation would be really helpful for us beginners. Thanks so much for making this great tutorial available!
Editor: Notice that the article talks about Good Aperture Range. We are suggesting what a good range is. There is no such thing as a 'good aperture' -- an aperture is basically just a hole that allows light in.
As far as the aperture range is concerned, a large aperture allows more light in and therefore allows us to take natural light picture (i.e. without flash) when there's not much light to go around. That's good. A large aperture also allows us to shorten the depth of field, important for occasions when we want to blur the background and have our subject stand out
in sharp contrast to the background. That is very good!
A small aperture allows us to limit the amount of light that comes into the camera and this allows us to use a slower shutter speed in bright lights for occasions when we want to depict motion, e.g. flowing water. [When it's still too bright, photographers use Neutral Density filter(s) to reduce the amount of light coming into the camera.] More importantly, a small aperture also increases depth of field and ensures that objects from near to far are all in sharp focus, as we like to have in landscapes. That is very good!
The sample images show that we can take good photos at all apertures. But a good range of apertures allow us to take more good photos, especially those that depend on depth of field
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