About Camera Bodies

Tom Davis
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Last Modified: May 11, 2003

There are literally hundreds of features available on various camera bodies, and many people who are considering the purchase of their first camera spend hours studying the various options available.

This can be a lot of fun to do, but keep in mind that you will hardly ever use most of those features. You will, however, use a lens on every shot, which is why it's far more important to pick a good lens than a good body.

Some people recommend that a beginner should get a totally manual body (like the Pentax 1000) and will thus be forced to learn the details of f-stops, exposure, shutter speeds, et cetera. See my detailed comments on this if you're interested.

I figure that if you get a camera you don't like to use, why bother? Almost any modern 35mm SLR will at least have the option of turning off all the automatic features so you can reduce it to a manual camera. I do recommend learning to use a camera in this mode -- you will become a better photographer as a result -- but even though I know how to use a camera this way I take better pictures by turning on and off the appropriate set of automatic features. If I'm shooting a flying bird, I'll get far more in-focus shots with a motor-drive and continuous auto-focus than the poor sucker who's trying to track the bird, wind the camera, and keep the focus manually.

On the other hand, there's less that can go wrong with a simple camera. I know people who love the Nikon FM2 -- it's totally manual except for the light meter, and even if the battery is dead, you can still take pictures -- all you lose is the metering which you can usually guess.

Your mileage may vary, of course, but I have never had any trouble with my fancy, complicated, modern bodies. When I'm traveling, I often take two bodies for insurance, but I've yet to have a failure. And I'm not talking about wimpy trips to Europe -- I'm talking about slogging through pouring rain in hip-deep mud in Ecuador.

Even the bottom-of-the-line automatic SLR bodies provide almost everything you need to take the vast majority of the shots you need. On the other hand, if you have an unlimited budget, go ahead and get the Nikon F5. Just be sure to get some really great lenses to go with it. (And be sure that you've done enough weight-training to haul that giant thing around. Or, I guess if you're rich enough, you can just hire somebody to haul it for you...)

The following lists don't pretend to be inclusive -- they simply list the sorts of features that I find extremely and moderately useful. My camera has plenty of features not on the list, and I do use them occasionally, but 99% of what I do is probably covered in the first list.

Highly useful features


Auto-focus uses electronics and optics to focus the lens. With enough light and if you're not using a long telephoto lens, it works great -- probably better and faster focus than you can get yourself. The speed and quality of autofocus depends heavily on computer power, so I predict that every year, it will get better, and it's great now.

Be sure you can disable this feature because there are times when it doesn't work, and when this happens, it's infuriating. There are also times when you can't get everything in focus (some stuff is close and some stuff is far away), and you want to manually focus mid-way between the two so nothing is too far out of focus.

Some cameras have two auto-focus modes. One is continuous, which tries to keep the item in the center of the image in focus no matter what, and the other focuses once on the center object, but as long as your finger keeps the shutter release half pressed, it doesn't try to re-focus. That way you can focus on something that's not in the center of the frame by locking the focus while it's in the center, and then moving the camera to recompose and put the object where you want it. Then push the shutter release all the way down, and you've got your photo. This second mode I find to be far more useful. The first mode is great for tracking moving objects, however. I also find that I use the continuous auto-focus mode a lot for macro shots.

Exposure modes

To take a well-exposed photo, the right amount of light has to get to the film. Ignoring flash for the moment, there are two ways to control this. You can either change the amount of time that the shutter is open, or you can change the aperture on the lens.

See the section on lenses for more details, but the f-stop setting on the lens controls how much light it will let through. You can make a smaller aperture by changing the size of an opening behind the lens.

In general, there isn't any "correct" setting of aperture and shutter speed. If you've got a pair of settings that gives the correct exposure, and you cut the size of the aperture in half (letting in half as much light), but double the time the shutter is open, then exactly the same amount of light will reach the film, and the exposure will be correct in both cases. (This is not strictly true, but it's close enough for the current discussion.)

But if you're taking photos of rapidly moving things (race cars, flying birds, 3 year olds) and the shutter is open for too long, you'll get blurry photos, so you may think that the thing to do is to always open the aperture as wide as possible to minimize the time the shutter is open.

Unfortunately, large apertures lead to a smaller depth of field, so less stuff in the photo will be in focus, so there is always a trade-off. The better you get at making this trade-off, the better a photographer you will be.

Typical automatic cameras have 4 expose modes:

I use program mode and aperture priority mode heavily. I occasionally use full manual mode and only very rarely the shutter priority mode.

TTL flash

This is a truly killer feature of modern cameras (assuming you use electronic flash). "TTL" stands for "Through The Lens" metering.

In the old days (or now, if you don't have a TTL system) you had to do a bunch of calculations to get the proper aperture depending on how powerful your flash was, how far away the subject was, and how many other things are nearby enough to affect the exposure.

With TTL, it all happens automatically. Inside the camera is a little light sensor that's looking at the film to see how much light is reflected off of it. When the flash goes off, it is not instantaneous -- it takes a few thousandths of a second to send out all it's light -- but as soon as the sensor watching the film notices that enough light has arrived for a proper exposure, the flash is electronically "quenched" -- turned off -- so exactly the right amount of light arrives at the film.


Motor drives are not essential for everyone, but they are very handy for shooting wildlife, so they're essential for me. Most animals are not trained to be great models, and it always seems that the instant you take the photo, the animal assumes a better pose, and without a motor drive, you may miss it.

Sea Otter For lots of nature photos, you just take a lot of shots and hope that one of them is good. Birds in flight are a great example. When you've got the right bird in the right light flying in the right direction, just treat the camera like a fully automatic machine gun and figure out what happened when the slides come back! The photo on the left is of a sea otter that I took in Monterey Bay. It was a beautiful sunny day, and I happened to have my big lens on a tripod. The otter was opening sea urchins by pounding them against a rock that it had on its belly. The motion was at blinding speed, and there was a lot of splashing. I simply pointed my camera at the otter, focused, and started taking groups of shots at five frames per second. I set a personal record that day of shooting an entire roll of 36 frames in less than 30 seconds.

Depending on the camera, various motor-drive modes are available.

The simplest just takes a photo every time you press the button, so even if you press the button down and hold it down, you only get one shot. Other modes are fully automatic -- as long as the shutter button is pressed (and there's film left) the camera will take shots continuously. Often, the rate that these photos are taken can be adjusted, to, say, 1, 3, or 5 frames per second for the Nikon F4.

When I put my F4 into 5 frame-per-second mode, and change the focus to continuous mode it feels like I'm arming a nuclear warhead (capable of doing $2.50 per second damage to my wallet with standard slide film). Clearly I "need" the F5 that shoots 8 frames per second, peak rate.

Other cameras have special motor drives that can be attached to them. Nikon sells (or sold at one time, I'm not sure if they still do) a motor drive capable of 10 frames per second. This burns a 36 shot roll of film in about 3 1/2 seconds, so the rumor was that every time Nikon sold one of these drives, they got a kick-back from Kodak!

Slightly less useful features

Exposure compensation

Usually, cameras have no idea what you're photographing (although the really modern ones are beginning to have some vague idea in an artificially-intelligent sort of way), so they assume that you're shooting "average" stuff. If you're photographing your black Newfoundland standing in a black lava field, or your white Great Pyrenees in the snow, your camera will be completely confused and will over-expose the black dog and under-expose the white one.

Exposure compensation lets you tell the camera to adjust what it's normally doing to account for this. Obviously you can do this using pure manual exposure mode, but if you're lazy, exposure compensation can speed things up.

The exposure compensation switch lets you automatically add or subtract some amount of exposure to every shot, so If you're on the Galápagos Islands shooting lots of critters on black lava, you can just set the exposure compensation dial to under-expose by 2/3 stop or maybe even a full stop, and never worry about it.

Of course then you'll forget you left it on, and when you shoot your next roll on the white sand beaches nearby, you'll totally underexpose everything.

Timed shutter release

Most cameras, even the cheapest, have this. Put the camera on a tripod (or more likely, balance it precariously on a rock), press the shutter, and run like hell to put yourself in the photo with all your buddies.

There are other uses for this, too. When you press the shutter, you tend to shake the camera. If you're taking a photo of something that's not moving and you want to minimize camera movement due to tripping the shutter, put it on a tripod, get everything focused, and then use the timed shutter release. You can also get a cable release, and that's what I'd normally recommend.

Special Program Modes

Some cameras have a set of special program modes (in addition to the one that gives fully automatic aperture and shutter speed selection). For example, there may be a "sports mode", where the camera assumes that you'll be taking photos with more motion than usual, so you'll probably want a higher shutter speed. Then instead of getting the same shutter speed/aperture selection that you'd have gotten in the vanilla program mode, the camera will opt for the higher shutter speed.

Similarly, in landscape photo mode, the reverse will occur. Since presumably you're using a wider-angle lens, you don't need that much shutter speed, and a smaller aperture will give better depth of field, so the camera closes down the diaphragm a bit and takes a longer, sharper photo.

There are other modes as well, but the above gives the idea. I personally find it's easier just to learn how the camera works.

Built-in Flash

Some camera bodies have a built-in flash that you can pop up if you need some extra light. Obviously, this will not be a terribly powerful flash, but it can be useful. I personally would not get one, but many people seem to love them. I just carry a good flash and hook it on when I need it. Since I carry a powerful flash anyway, it seems silly to pay extra for a flash on the body that I will almost never use.

One of the disadvantages of the built-in flash is that it almost always appears on camera bodies that use (expensive) lithium batteries, and the flash will use those batteries up in a real hurry.

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