Buying Camera Lenses
As when buying a camera, it's a good idea to research the kinds of lenses you're interested in before making a purchase. For the most part, lenses are divided into three quality categories:
Professional lenses: More expensive, generally sharper, and better built. Faster f-stops, better mechanics, better optical qualities. You even get more contrast and better color from better lenses. The better lenses will stand out, especially when the images are greatly enlarged.
Consumer lenses: Might only be good enough for prints up to 4″ × 6″ or 5″ × 7″. Less expensive lenses are also not going to be as fast — their largest aperture may not be large enough and may introduce distortions, such as not portraying parallel lines accurately.
“Pro-sumer” lenses: Offer features and qualities that fall between consumer and professional, priced accordingly.
Learn about variations in model designations or lens series so you know what you are getting and what a fair price would be. Don't pay pro prices for bargain lenses; keep in mind, however, that price is definitely an indication of quality and performance. Lenses with better optical elements and larger maximum apertures will always cost more than lenses with lower quality optics and smaller maximum openings.
Be sure to buy the right style of lens for your camera. Manual-focus lenses won't always work on autofocus cameras and vice versa, although they are sometimes semicompatible. A lens with a mount designed to work on one camera brand won't work on other brands.
The same companies that manufacture camera bodies also offer lenses that match their cameras. These lenses are designed to work with the manufacturer's cameras only, so they can't be swapped between cameras made by different manufacturers. Buying these lenses will assure a perfect interface between camera and body and will virtually eliminate any performance errors that might happen with lenses made by another manufacturer. Professional photographers usually stick with top brand-name lenses that match their cameras.
Aftermarket companies make several versions of the same lens to fit different cameras. The difference between these versions is simply the physical and mechanical interface, which is different for each camera manufacturer. Like the major names, they divide their products into professionally oriented lenses and consumer lenses. Some individual lenses by these aftermarket companies are quite good. Do your research to decide what is right for you.
It is always a good idea to buy a lens from a store that allows returns. You should always test a new lens by shooting a few rolls, or the digital equivalent. You might find the lens is not as sharp as you had hoped, or maybe it has a focusing problem. Even if you don't need to return the lens, be sure to keep the receipt and the box it came in. If you ever want to sell the lens or need to have it serviced, it's a good idea to have both.
Whether your equipment is new or used, be aware that there can be variations in quality between the exact same lenses. One 35mm f/2.8 Yukon may be sharper or softer than the seemingly identical 35mm f/2.8 Yukon sitting on the shelf next to it. A used lens may be on the market because it didn't measure up.
There is no ideal zoom lens that works for everyone. If you love taking group pictures inside your home, you'll want a zoom that stays in the wide-angle range, like a 24mm–50mm. If you like to do head-and-shoulder portraits as well as shots of small groups indoors, then a 35mm–105mm is a large enough range. If you are into sports and outdoor activities, you will want a zoom that goes at least to 200mm. Keep in mind that the larger the zoom range and the longer the telephoto, the heavier the lens will be. This is a concern if you need to lug your gear around or if you suffer from carpal tunnel syndrome.
New SLR cameras sometimes come packaged with a 28mm–70mm or 28mm–80mm medium-range zoom. These focal lengths cover many picture-taking situations, but they may not be what you want. If so, ask about substituting a zoom that matches your needs or see if you can buy the body and lens separately.