Lens technology has improved by leaps and bounds over the last decade. Computerized lens designs and advances like aspherical lens elements and chemical lens coatings have practically eliminated color aberration, lens flare and other less-than-desirable side effects of optical construction. New lens designs typically are more compact, too. Many are created specifically for smaller, sub-35mm sensors, so the optics themselves can be smaller. Digital camera bodies and lenses also are able to communicate far more effectively for extremely fast and accurate autofocus and metering. It’s a great time to be looking for that perfect zoom.
FROM WIDE TO TELE
The size of your camera’s imaging sensor determines the effective focal range of your lenses. When used with cameras with “full-frame,” 35mm-sized sensors, lenses will perform normally. When used with sub-full-frame sensors, there’s a magnification effect, which essentially crops the image and creates a telephoto effect. This magnification is about 1.5x, so a 16mm lens on a sub-full-frame camera will deliver a field of view like a 24mm lens on a full-frame camera.
This is a benefit for telephoto performance: stronger telephoto from a lighter, smaller lens. For wide-angle perspectives, you’ll need a wider lens than you would with a 35mm-sized sensor. Many of the lenses we feature here start their range at 18mm, which translates to about 27mm when used on a sub-full-frame camera.
The farther out you are in your zoom range, the more prevalent shaking will be in your image capture, so with long range it’s incredibly important to use a tripod, fast shutter speeds and/or image stabilization. Canon and Nikon offer image stabilization built in to select lenses. Other manufacturers like Olympus, Pentax and Sony have built image stabilization into their camera bodies, so it works with every lens. Both systems provide up to four stops of shake compensation for shooting at slower shutter speeds.
When buying a lens, keep an eye on its maximum aperture. Lenses with larger maximum apertures can let in more light, allowing you to shoot in dimmer conditions without having to boost ISO. Larger apertures also create a pleasing blur in the background, ideal for isolating a subject. When deciding between a more expensive lens with a wider aperture and a less expensive one with a smaller aperture, it’s often best to go with the larger aperture, if possible. Many zoom lenses have a variable maximum aperture, which means that the maximum aperture decreases as you zoom. The complexities of lens design make a long zoom with a fixed aperture a particularly expensive item to produce, so manufacturers offer more cost-effective, variable-aperture zoom lenses.