Everything You Need to Know to Buy Your First DSLR

Posted 08/22/2011 at 2:03pm | by Loyd Case

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Tired of missing those action shots? Are blurry indoor photos getting you down? A DSLR might be just the cure for your point-and-shoot blues

Phones with cameras are ubiquitous, and point-and-shoot cameras have become practically throwaway purchases. It’s the golden age of citizen photography, but as you become more serious about your images, pocketable cameras become more frustrating, and you run into the limits of physics. The tiny sensors and low-speed lenses in camera phones and point-and-shoots can’t do justice to fast-action or low-light photography. Sometimes when you need that really long shot of, say, a hawk soaring above the trees, the wide-angle lens common to compact cameras reduces the graceful lines of the regal bird to a tiny dot.

Enter digital SLR (single-lens reflex) cameras, which take your photography to the next level. “SLR” simply means that a mirror or prism sits in front of the sensor and directs light to an optical viewfinder, allowing you to monitor the scene as the lens sees it.

A DSLR offers a larger sensor than you’ll find in a point-and-shoot camera, and this allows it to capture more light. The larger sensor also offers greater dynamic range, which often translates to better shadow detail in photos with mixed lighting. A DSLR also gives you fine-grain control over all your picture settings—aperture, shutter speed, focus, ISO settings, and more.

Interchangeable lenses are another big selling point. For normal use, you can use a lightweight zoom that’s suitable for general photography. For long shots, add a superzoom or long telephoto. The combination of bigger sensors, infinitely flexible settings, and robust lens choices allows you to capture phenomenal action, shoot in dimly lit conditions, or sometimes both.

The two leading manufacturers of DSLRs are Canon and Nikon, which together own nearly three-quarters of the market. In the following pages, we'll help you determine which DSLR features are right for you and review some of the interesting models.

Before You Buy

ASK YOURSELF: WHAT KIND OF PHOTOGRAPHER AM I?

How you plan to use your DSLR camera will inform your purchase and help you parse the myriad camera specs thrown at you by DSLR makers.

SENSOR SIZE
DSLR sensors come in two general sizes: Advanced Photo System type-C (APS-C) and full frame. “Full frame” refers to a sensor roughly the same size as a 35mm film frame. Most APS-C sensors offer crop factors of roughly 1.5–1.6x of that. Generally, a full-frame sensor offers better low-light performance, while an APS sensor offers better reach. A 50mm lens on an APS-C sensor camera is equivalent to a 75mm lens on a full‑frame sensor. So if you’re shooting long—say, football fields or wildlife—a 300mm lens will give you an equivalent 450mm reach. The crop factor also has an effect on depth of field: Full-frame sensors yield shallower depth of field, which often makes them desirable for portrait photography. Crop sensors are good for landscapes, providing not only more reach but deeper DOF.

MEGAPIXELS
This is the number of effective pixels in a sensor. Modern DSLRs typically have 12MP or more. More pixels do not always mean better photos. Very high pixel densities sometimes cause less sharpness when your lens is stopped way down to f/16 or higher (smaller aperture). Macro photographers often want extreme depth of field and need to stop down—but not if they lose effective sharpness. Given the relatively high megapixel counts of modern DSLRs, this is one spec that’s increasingly irrelevant—18 megapixels isn’t better than 14.

FRAME RATE
DSLRs offer continuous shooting modes, which is a boon for shooting action photography. At a minimum, you’ll want to be able to shoot at 4 frames per second. At 6fps, you miss less of the action in fast-moving sports.

BUFFER SIZE
The buffer is a temporary fast memory cache used to hold photos while they’re written to much slower flash memory cards. You’ll want a big buffer if you’re shooting at high frame rates. It’s frustrating to miss critical action waiting for the buffer to flush to a memory card, which happens with even very fast memory cards.

AUTOFOCUS POINTS
Most users tend to focus in the center of the viewfinder; it feels natural. A good DSLR will have multiple focus points, letting you focus to one side, or above or below the center. That’s very handy if you want to draw attention to a part of the photo to one side.

SCENE MODES
It’s tough to let go of some handholding, so most consumer and prosumer DSLRs have some automation of modes, like portrait, landscape, night, etc. The more capable DSLRs allow you to create custom settings based on your preferences, which is often better than an automated mode.

ISO SETTINGS
ISO numbers refer to the light sensitivity of the sensor. All digital camera sensors have an optimal ISO that captures the scene with minimal noise. Increasing the ISO number allows you to shoot in lower‑light conditions, but you’ll see more digital noise in the photo. Auto ISO, long a staple of point-and-shoot cameras, is now common in DSLRs, as they let the camera pick the optimal ISO setting for the combination of shutter speed and aperture setting.

VIDEO
Most current-generation DSLRs can shoot video. The variation of video capabilities is wide, however, with some cameras capable of shooting up to 1080p/30fps while others can only manage 720p. When using a DSLR for video, you gain access to a wide array of lenses, but you also lose some features, like the fast autofocus capability used when shooting still images.

MEMORY CARDS
All the cameras we tested use SD cards (including SDHC and SDXC) for storing photos. The Nikon D7000 actually supports twin SD card slots. Pro DSLRs often use CompactFlash, which generally offers higher capacities and faster writes than SD cards, but the latest SDXC cards use UHS controllers capable of 104MB/s write speeds. The camera body needs to support UHS speeds to take advantage of the full performance of these newer cards, however.

LIVE VIEW
One of the DSLR's strengths is its abilty to shoot through the optical viewfinder, but the new generation of DSLRs can also use an LCD display on the back to show the scene. This is often the mode used to shoot video. Some DSLRs offer articulated LCD screens, which allow for more flexible shooting angles.

FLASH
Cameras in the class we tested all have built-in flash. They go a step beyond the pop-up flash built into many point-and-shoot cameras, though, allowing the camera to control multiple remote external flashes with the built-in flash. This allows for incredible flexibility in lighting.

Putting a DSLR to the Test

Testing the performance of a DSLR can be a complex process, but we distilled our testing down to a few key parameters. We wanted to check out image quality at high-ISO settings and continuous-mode shooting performance as objectively as possible. Autofocus performance was a tougher nut, since modern DSLRs tend to offer pretty fast autofocus under normal lighting. So we settled for subjectively testing AF “hunting” in a low-contrast environment, which is probably the biggest challenge for most autofocus schemes.

High-ISO testing was conducted with roughly equivalent, higher-quality lenses. For Nikon, we used the new Nikkor AF-S 24-120mm f/4G VR. For Canon, the test lens was the EF 24-105mm f/4 IS USM. The cameras were set to aperture priority mode and f/5.6, with the shutter speed allowed to vary. The room was moderately lit with old-style fluorescent tubes, which also gave us a chance to check out the effectiveness of the auto white-balance.

The scene used in high-ISO testing consisted of a number of colorful objects on a white background. We then cropped an 800x800 pixel region that contains a sample of most of the objects used and looked at noise levels at ISO 800, 1600, 3200, 6400, and 12800. We made sure to disable both noise reduction and sharpening in Photoshop’s Camera Raw tool when we imported the images to Photoshop.

Continuous-mode testing was performed with a cleanly formatted, SanDisk Extreme SDXC card with a rated throughput of 45MB/s. The cameras were set to manual, 1/250 of a second, f/4, at the maximum continuous mode of the SLR.

We discuss the results of continuous-mode shooting in the individual reviews, but all these cameras have limited buffer sizes, particularly if you’re shooting in raw mode. Getting a faster SD card helps, but only to a limited extent.

Our high ISO test shots consist of an 800x800-pixel section of a larger image. While it's hard to discern differences in thumbnails, in Photoshop, variations in image noise are apparent.