How to buy: DSLR cameras Page 3 of 6

Digital single-lens reflex cameras aren’t just for professional photographers anymore

Lenses

You’ll need a lens to go with your new camera. All the cameras we looked at for this roundup come in kits that include a decent starter lens. These lenses are small and lightweight, produce good-quality images, and offer focal-length ranges of 18mm to 202mm in 35mm terms—that is, wide to telephoto.

There are many factors that make one lens more expensive than another. Pricier lenses have higher-quality glass, which, for a number of reasons, can yield better sharpness and contrast to make a nicer-looking image overall. Higher-quality lenses also often allow for a wider maximum aperture. For example, a 3.5 lens has a maximum aperture of f/3.5, while a 1.8 lens has a maximum aperture of f/1.8. A 1.8 lens is considered faster than a 3.5 lens because it gathers light so quickly that it can operate with a very wide aperture.

Faster lenses allow you to shoot in lower light and let you capture images with a shallower depth of field, offering the promise of greater creative control. However, faster lenses are usually larger and almost always more expensive than slower lenses.

Lenses can be grouped into two categories: zoom lenses, which you’re already used to from your point-and-shoot camera, and prime lenses, which offer one focal length. Prime lenses are generally faster than zoom lenses and often yield better quality than a zoom lens with an equivalent focal length.

Note that on a zoom lens, the maximum aperture often varies depending on the focal length you’ve selected. A zoom lens might have an aperture range from f/4 to f/5.6, meaning that it can shoot at f/4 at its widest angle but can manage only f/5.6 at its most telephoto angle.

If you’re new to SLR shooting, stick with the kit lens for a while. You can buy new lenses later. With practice, you’ll get a better understanding of what you need in a lens. Your lens collection can grow as your photographic skills do.

Cropping factor

Because most DSLRs have sensors that are smaller than 35mm, their field of view is narrower than that of a 35mm camera. If you have experience shooting with film cameras, then you’re probably used to the idea that a 50mm lens (often called a portrait lens) has about the same field of view as your eye. Longer focal lengths are telephoto (they magnify) while shorter focal lengths are wide angle (they can capture a wider distance in a single shot).

The field of view that a lens of a given focal length provides depends on the size of the imaging medium (be it film or a digital memory card) that sits on the focal plane. For example, if you were to put a 50mm lens on a digital camera such as the Canon Digital Rebel XTi, you’d have a field of view equivalent to an 80mm lens on a 35mm film camera, because the sensor in the XTi is small enough so that any lens has a 1.6x cropping factor. That is, you should multiply the focal length of any lens you place on the camera by 1.6 to find its 35mm focal-length equivalent.

All the cameras in this review have a cropping factor.