Cameras beyond the beginner and step-up categories are usually sold with just the camera body. Manufacturers assume that you already have at least one DSLR camera, own one or more lenses that you'll want to use, and have bought the same make of camera as before. If this isn't the case, or you want something different than the fairly basic kit lens that came with your beginner or step-up DSLR, you'll need to buy a new lens. We examine expert reviews of DSLR lenses, but there's no overall consensus as to which ones are best; it depends in part on the model of camera you use. Here are some things to consider before making your lens purchase.
Manufacturer versus third party
Lenses from one camera manufacturer typically won't fit on another manufacturer's cameras, so Canon lenses, for example, won't work on Nikon cameras. However, third-party lens manufacturers such as Sigma and Tamron make lenses in a number of different mounts to fit multiple camera brands. Some are rated highly in expert reviews, but autofocus may be slowed when using such third-party lenses.
Unless you're changing camera companies, when you buy a new camera you'll want to be able to use your old lenses on it. Nikon is renowned as the company with the most backward-compatible lenses; their F-mount lenses from 1959 will still fit today's cameras. Other companies may require you to purchase adapters to use older lenses, so check this out when buying your camera.
Zoom versus Prime lens
Zoom lenses, with their convenient range of focal lengths, have become the standard type of lens on DSLR cameras. But some experts argue that Prime lenses with just one focal length have advantages. They're generally smaller and lighter than zoom lenses, have faster maximum apertures and produce sharper images. If you know you're going to be shooting a lot in a particular setting that calls for a specific focal length of lens, like low light, consider a Prime lens.
If you're a photographer who shoots in the rugged outdoors, you've probably chosen a weather-sealed camera. But the hardiness of the camera is only as good as the durability and weather-resistance of the lens you use. The more expensive lenses are generally more durable, and some have environmental seals so they're water- and dust-resistant. Pentax, in particular, makes a WR series of weather-resistant lenses for its top-of-the-line K5 series of DSLR cameras.
Depending on the camera manufacturer, the autofocus system is either in the camera itself or in the lens. In the reviews we examined for this report, many experts comment on the loud noise of the autofocus systems of the cameras they tested. If your camera has the autofocus in the lens and silent photography is important to you, test it out before buying.