A digital SLR camera is the dream toy for most photographers. We rounded up the major players in the market and put them to the test.

For photographers who want maximum control over their images, nothing beats a single-lens reflex camera, or SLR. Digital SLRs used to be so expensive that only professionals could afford them, but that is changing rapidly. Cameras such as Canon’s EOS-300D, which debuted two years ago at £765 plus VAT, have lowered the bar for consumers in terms of the cost of entering the market.

These low-cost cameras let consumers enjoy professional-grade features and capture great-looking images in difficult shooting environments. Most important, they don’t necessitate any big trade-offs – you will get much of the functionality of high-priced SLRs.

We put seven of the latest SLRs through our newly expanded battery of tests. We looked at four low-priced SLRs and three more-expensive models.

The most obvious advantage SLRs offer is the ability to swap lenses to suit a particular shooting situation. SLR lenses can achieve very small aperture sizes, down to f22, compared with a limit of f8 found on many fixed lenses. SLRs also tend to be able to shoot at a wider range of speeds.

All the models here can shoot in increments as long as 30 seconds. The Canon EOS 20D and Nikon D70s can shoot as fast as 1/8,000 second, while the others can shoot as rapidly as 1/4,000 second. Advanced point-&-shoot models, in contrast, usually have a range of shooting speeds from about 2 seconds to 1/3,000 second.

Keep in mind that because the image sensors in most digital SLRs are smaller than a frame of 35mm film, the focal length is affected. Usually you have to multiply by 1.5 or 1.6 to get the 35mm equivalent of a lens when you place it on a digital SLR. For example, a 28mm-to-80mm lens for a film SLR will yield the equivalent of roughly 42mm to 120mm on a digital model. The exception is the Olympus E-300 – for that camera’s lenses you must multiply by two.

SLRs also tout high ISO settings, mimicking the film-speed ratings of 35mm film. An SLR’s sensor is highly sensitive to light, which can be particularly helpful when you’re shooting without a flash or tripod in dim light. SLRs frequently offer up to ISO 1600 (though two of the cameras we looked at, the Konica Minolta Dynax 7D and the Pentax *ist DS, go up to ISO 3200), while advanced point-&-shoot cameras often top out at ISO 400. Their expanded range makes SLR units much more capable in situations where low light and fast movement can make capturing a high-quality image difficult.

Stay focused

An SLR camera’s autofocus tends to be sophisticated, though you may prefer manually using the focal ring on the lens in some situations, such as when you’re shooting in dim light or photographing a small object in macro mode. The fixed lenses on most advanced point-&-shoot cameras lack a focal ring.

Another reason SLRs are superior for manual focusing is that you look through their lens rather than at an image on an LCD or electronic viewfinder. The focal ring on most of the lenses that we tested operated smoothly, though the 18mm-to-55mm EFS lens on the Canon EOS-350D felt a little loose and was less responsive than most others. Also, turning the EFS lens’ focal ring moves the entire front section of the barrel, which will change the effects of certain filters.

Unlike the other focal rings we tried, which move glass inside the lens mechanically, the focal ring on the Olympus E-300’s lens is connected by wire to an electronic motor. This method lacks the tactile feedback the other lenses provide, but we found the mechanism helpful for fine-tuning the autofocus.

SLRs power up quickly, as well. The Nikon D70s was particularly speedy, ready to shoot in less than a second. And, because SLRs have a burst mode, you can shoot continuously while you hold down the shutter button. Burst modes on SLRs are superfast – even bargain models can take as many as three shots a second. Depending on the image-quality setting you use, some cameras can shoot more than 100 frames at a stretch.

For example, if you use a high-speed CompactFlash card with the Nikon D70s, the camera is rated to take 144 frames in burst mode at the JPG Normal-Large setting. However, with a standard CompactFlash card and the Fine setting (3,008-x-2,000 pixels), the D70s fired off just 10 successive images before it stopped shooting continuously, and was then capable of capturing only about one frame per second (fps). The Olympus E-300’s burst mode, rated at 2.5fps, was impressive, too. The camera never noticeably slowed when shooting 200 consecutive high-quality JPGs and stopped only when it had filled a 256MB CompactFlash card.

Almost all of the SLRs we looked at excelled in terms of battery life. Every camera but one reached the maximum of 500 shots that our battery tests specify. The only model to fall short of that mark was the Konica Minolta Dynax 7D, which gave in after just 278 shots.

The Fujifilm FinePix S2 Pro’s hulking body has two battery compartments – one for two 3-volt disposable lithium batteries, and the other for four AA batteries. Although the S2 Pro has two media card slots, the second slot is for SmartMedia cards. SmartMedia cards top out at 128MB, so you’ll soon have to grab a replacement CompactFlash card if you want to keep shooting. An SD Card slot would have made much more sense.

Noisy work

Digital cameras offer a distinct benefit in their ability to change their ISO without your having to swap film (or carry multiple cameras loaded with a different film). However, like the grainy shots you get when using high-ISO 35mm film, digital images shot at higher ISO settings tend to have more digital noise.

When it came to minimizing noise at a range of ISOs, the Konica Minolta Dynax 7D and the Canon EOS 20D performed best, introducing very little noise even at ISO 1600. The Konica Minolta Dynax 7D and the Pentax *ist DS are the only two cameras here that can shoot at ISO 3200, though at that setting both cameras produced noisy images. The Olympus E-300, which shoots at up to ISO 1600, received the lowest score in our noise tests.

You don’t have to shoot at a high ISO setting to see distortions, however. Some of the photographs we took using each camera’s lowest available ISO setting contained noticeable artifacts.

The Nikon D70s introduced the most glaring colour interference. The Pentax *ist DS produced the haziest image of fine details, while the Canon 20D rendered the sharpest image. Among the lower-cost SLRs, the Canon EOS-350D introduced the fewest colour artifacts and the least distortion. Though you may not notice such artifacts in an uncropped image printed at 8-x-10-inches, being able to crop closely and make a large print without distracting distortions gives you a lot of flexibility. By comparison, advanced point-&-shoots tend to produce a lot more noise at lower ISOs than any of the SLRs we tested.

Unique features

In an effort to distinguish themselves, some SLRs tout potentially innovative features. The Olympus E-300 uses predictive focusing, which attempts to forecast where your moving subject will be when you trip the shutter. In images taken of fast-moving cars both with and without predictive focusing, the E-300 showed no difference in sharpness. More important, if anything, is how quickly (or slowly) a camera focuses in the first place – many of the E-300’s photos showed only half of a car in them because the camera was frustratingly slow to lock on focus and trigger the shutter. By contrast, the autofocus on the Nikon D70s was snappy, managing to capture a running dog. The camera’s rapid 1/8,000 shutter speed didn’t hurt either.

The E-300 has an internal mechanism for fighting dust. It’s a filter that sits between the shutter and the sensor to catch dust particles. Changing lenses on an SLR exposes the camera’s interior to dust, which can show up on your images. Getting dust out of a camera can be exasperating, so this is a good idea.

The Konica Minolta Dynax 7D boasts anti-shake technology built into the camera body. In our informal tests, the 7D’s sensor effectively compensated for restless subjects and shaky hands, producing noticeably sharper photos than we obtained after turning off anti-shaking. Many cameras put this feature in their lenses, which may make the lenses more expensive. Most of the kit lenses sold with low-cost SLRs add about £60 to the cost of the camera (and don’t include an anti-shake feature). By contrast, prices for Canon’s 28mm-to-135mm lens with image stabilization range from around £220 to £320.