If you're a first-time SLR shopper you're purchasing more than just a camera, you're buying into a camera system. If you buy an extra lens or two, a flash, or other add-ons, you'll be able to take them with you to your next camera—and good glass often equals or exceeds the price of the camera itself, so this is no small factor. There are a wealth of interchangeable lens systems on the market today, including mirrorless cameras, fixed-mirror SLRs with electronic viewfinders from Sony, and traditional D-SLRs.
If you've already read our Digital SLR buying guide and have decided on a traditional D-SLR, you're left with three brand choices: Canon, Nikon, and Pentax. The latter is the smallest of the three in terms of market share, but offers a number of bodies and lenses that are fully weather sealed, like the Pentax K-30$578.99 at Amazon. The strength of the Pentax system relies in compact fixed focal length lenses, so you'll have more zoom lens options with Nikon or Canon, as well as the ability to eventually upgrade to a full-frame camera, which is currently lacking from the Pentax digital catalog.
Playing the numbers, most buyers will opt for one of the big two, and doing so gives you access to the widest variety of lenses and accessories. If you've decided that you feel most comfortable in the big-tent world of Canon or Nikon, you'll still have to decide between the two. This guide should help you make that decision.
The Camera
Nikon D3100Both companies have a few entry-level (under-$1,000) SLR models that ship with an 18-55mm starter lens. These bodies use APS-C image sensors, which are roughly 75 percent the size of a 35mm film frame when measured diagonally. Because digital SLR lens mounts are based on older 35mm film standards, you'll hear a lot about the crop factor when it comes to using lenses on these APS-C bodies; the 18-55mm zoom is roughly the same as a 28-80mm on a 35mm or full-frame digital camera.
Canon's current entry-level D-SLR is the EOS Rebel T3$399.00 at Amazon; it's priced at $549.99 with a lens, but it's an older model, and is available for less online. It's not dissimilar in features to Nikon's entry-level body, theD3100$414.00 at Amazon (above), which lists at $649.95, but is also a bit older and selling for less. Both cameras feature fixed rear LCDs, use pentamirror-style viewfinders, are limited to shooting at 3 frames per second, and have basic autofocus systems that can hold their own when using the optical viewfinder, but are a bit slow when you shoot in Live View mode, using the LCD to frame your shots.
As entry models, they both feature a Guide Mode, which will help you learn more about the camera's functions, and in addition to the standard Automatic, Program, Aperture, Shutter, and Manual SLR shooting modes, they offer point-and-shoot style Scene Modes. This optimizes camera settings to capture what you are shooting—there are common modes for fast action, low light, snowy scenes, and others.
Canon EOS Rebel T4IWhen you move up to more expensive bodies, features increase in kind on both sides of the fence. The Canon EOS Rebel T4i (left) and the Nikon D5100$699.95 at Amazon add faster continuous shooting and articulating rear displays (the T4i's is touch-sensitive) and if you move up to a more advanced model like the Canon EOS 7D$1,299.00 at Amazon or the Nikon D7100 you get better autofocus, more physical controls, and a larger pentaprism viewfinder. The bottom line is that features are similar at similar price points—Canon may have a slight edge in video autofocus with the T4i, but only if you use one of two available STM lenses, but the similar Nikon D5200 has a more advanced autofocus system and offers an optional Wi-Fi adapter.
Nikon is alone in having a pair of cameras available that omit the optical low pass filter. Most professional medium format cameras skip this filter as well, as it reduces image sharpness. This comes at a risk of color moiré, an unwanted rainbow color pattern, when shooting certain fabrics or textures—but if that unwanted effect pops up in your images, it can be removed using tools in Lightroom and Photoshop. The full-frame D800E, which packs a 36-megapixel sensor (the highest resolution of any current Nikon or Canon SLR) removes the OLPF from its design, as does the company's flagship APS-C model, the 24-megapixel D7100.
Lens Compatibility
If you have an old 35mm Nikon or Canon camera lying around gathering dust, there's a chance that you'll be able to use your lenses on a D-SLR. When Canon moved from manual focus to autofocus in the 1980s it changed its lens mount, so you can't use manual focus lenses for FD mount cameras like the venerable Canon AE-1 on a Canon D-SLR. However, if you have a more recent Canon EOS 35mm film camera, any lenses that you own will mount and work on a Canon digital SLR.
Nikon Nikkor 50mm f/1.2 AI-SNikon D-SLRs can use most Nikon lenses made after 1977, like the manual focus 50mm f/1.2 shown to the right, but there are a few exceptions. The Nikonians web site has a full compatibility chart, but of course a manual focus lens won't somehow gain the ability to autofocus on a newer camera. And if you're used to an old film camera, the field of view of your older lenses will be narrowed when mounted on an APS-C D-SLR. These lenses still capture the same amount of light, but since the sensor is physically smaller, information around it is not recorded. If you have an old SLR with a trusty 50mm standard-angle prime lens, it will act more like a short telephoto 75mm on an entry-level D-SLR.
If you use modern lenses, the crop factor isn't a huge deal as many are now designed with the smaller sensors in mind. An 18mm focal length on a full-frame camera captures such a wide field of view that you'll want to be careful not to get your fingers in the frame, but mounting the same lens to an APS-C camera produces a more moderate field of view, akin to a 28mm lens on a full-frame body.
Canon EOS 6DBecause of this, the kit lens that ships with your D-SLR doesn't cover the image circle of a 35mm film frame. Canon uses an EF-S designation for these APS-C lenses, while Nikon refers to them as DX. The key difference between the systems is that Canon EF-S lenses will only work with an APS-C camera; they will not fit on a full-frame body like the Canon EOS 6D$1,699.99 at Dell (left). Nikon DX lenses can mount on a Nikon full-frame camera, like the D600$1,559.00 at Amazon, in a special crop mode that simply uses a smaller area of the image sensor to capture a photo.
If you do find yourself bitten by the photographic bug and want to upgrade to a full-frame body down the road, Nikon's system gives you more room to grow. The standard 18-55mm kit lens isn't anything special, and you'll likely want to replace it with a nicer zoom if your photographic interests elevate. The Canon EF-S 17-55mm f/2.8 IS USM$879.00 at Unique Photo is an excellent lens that is priced at close to $1,200, but you won't be able to use it on a full-frame Canon camera. Nikon's similar 17-55mm AF-S DX Zoom-Nikkor 17-55mm f/2.8G IF-ED will work on an FX Nikon camera, but photos will be recorded at a reduced resolution and you'll still be limited to an approximate 25-80mm field of view.
You can always future-proof yourself and simply buy full-frame lenses. Almost all of Canon's non-zooming lenses are all EF, and you can opt to buy high-quality EF zooms as well—although they'll take more money out of your pocket. A year ago this compatibility issue wasn't as important as it is today, but full-frame cameras are coming down in price to the point where more and more photographic enthusiasts are enjoying the benefits of a larger image sensor—which included better performance in low light and the ability to create an extremely shallow depth of field so that you get a very blurry background behind your subject. Right now the cost of entry is around $2,000, but I wouldn't be surprised if that figure decreases over the next few years.