Have a question about today's best lenses? Here are all the answers you need.
Since Pop Photo began its improved lens-testing program in 1988, we have done full Lab tests on 444 interchangeable optics for SLR and rangefinder cameras, both film and digital. What we've learned could fill a book-but we'll spare you, and instead answer 10 of the most common questions photo enthusiasts ask.
1. What's better, an image-stabilized lens or a fast (bright) lens?
An IS lens counteracts only your motion, but a fast lens can counteract both your movement and your subject's by transmitting more light, letting you use a faster shutter speed to freeze motion and reduce blur when handholding. IS, no matter how effective, won't sharpen a running tyke photographed at 1/15 sec.
If you shoot a lot of action, you'll want a fast lens. If you take a lot of handheld, low-light candids of stationary subjects, you'll want stabilization. Best of all, of course, is a fast lens and stabilization (in-lens or in-camera). Tests of lenses such as Canon's 17-55mm f/2.8 EF-S IS USM ($1,000, street) prove the point.
2. Does a high price buy a better lens?
If "better" means simply sharper, no. Many inexpensive lenses test with sharpness comparable to (and sometimes slightly better than) pricier lenses with equivalent focal lengths. But if "better" entails all factors-optical performance, build quality, brightness, convenience-yes, you get what you pay for.
Case in point: two Canon EF zooms with nearly the same focal range, the 55-200mm f/4.5-5.6 EF ($210, street) and the 70-200mm f/2.8L EF IS ($1,700, street). A glance at our SQF charts shows the pricier optic earns great scores at three tested focal lengths-Excellent (70mm), Excellent (135mm), and Very Good (200mm)-while the bargain lens scores just one grade down-Very Good (55mm), Very Good (135mm), and Good (200mm). The more expensive lens doesn't win by much on distortion, either.
Is that worth a $1,500 premium? Maybe not, but consider: The L lens gives you 2 full stops' more brightness at longer settings. Besides allowing you to shoot in lower light, this lets you limit depth of field to blur out distracting backgrounds.
And, as photographer Michael Soo notes, the pricier lens has more pleasing bokeh-out-of-focus circles. See how his shot taken with the L lens (below, right) has regular, rounded, blurry spots of background light, while the bargain lens makes lumpy, asymmetrical ones (below, left). It may seem a minor point, but not to serious shooters.
Then there's build-the metal-barreled L lens will stand up to far more abuse than the plastic-barreled 55-200mm. Plus, it has image stabilization. And the rotating front filter ring of the 55-200mm will drive users of filters mad. Still, Soo says, "the 55-200mm is really easy to carry around and handle, because it's light-the 70-200mm L is at least five times heavier."
Another interesting comparison: the 18-70mm f/3.5-5.6 Sony DT ($190, street) versus the 16-80mm f/3.5-4.5 Zeiss Vario-Sonnar ($690, street) for Sony DSLRs. The standard Sony kit lens is such a standout that we wondered if a Zeiss could outdo it. Well, the mighty metal-barreled Zeiss was an order of magnitude sharper than the plastic Sony, due to superior control of chromatic aberration and less color fringing and edge softness.
3. Are lenses by the independent makers as good as those by the camera makers?
Often, yes. Over the years we've seen many examples where the lenses from the top three independents-Sigma, Tamron, Tokina-perform on a par with equivalent lenses from the camera makers, and occasionally even better.
For instance, we recently tested the Sigma 18-200mm f/3.5-6.3 DC OS AF zoom, which performed optically a notch better than Nikon's 18-200mm f/3.5-5.6G DX Nikkor VR AF-S ($700, street) and about on a par with Canon's most comparable zoom, the 28-300mm f/3.5-5.6L IS USM ($2,200, street). The image stabilization of the three lenses was competitive (Canon and Sigma, 2-3 stops' advantage; Nikon, 3-4 stops'). The Sigma, at $549 (street), costs $130 less than the Nikon and $1,650 less than the Canon.
Of course, like the camera makers, the independents have multiple lens lines, and their premium-grade optics can be nearly as expensive as the camera makers' top glass. Similarly, kit lenses and other inexpensive zooms from camera makers can challenge the independents on both price and quality. So know what you want in a lens, and consult our lens tests.
4. Are macros really sharper for close-up work than close-focusing zooms?
Yes. True macro lenses (which we define as able to focus to at least 1:2, or one-half life size) are more than optics that can simply be focused to less than a few inches. Their optical formulas have been devised to make sharp images at very close distances. Those designed for general photography, on the other hand, are optimized for moderate distances.
That said, the difference in performance has become narrower in recent years. A major reason: the use of floating-element systems that modify the optical formula of the lens at different focusing distances.
For instance, Nikon's 105mm f/2.8G VR and Sigma's 70mm f/2.8 EX DG Macro AF both turn in stellar performance at normal distances as well as closeup. (In fact, Sigma's may be the sharpest optic in its current lens line.)
The truly compelling reason to use a macro, though, is that they are just more convenient. You can focus to high magnifications without any extra tubes or front-mounting lenses-exactly the sort of accessories that can degrade performance of general-purpose lenses-and they are more compact than most tele-zooms. And while some zooms may provide pretty good macro performance, it's often at a single focal length, and often a very inconvenient one.
5. Is it true that single-focal-length lenses outperform zooms?
No. That was true years ago, but no longer. Within any given price range, zooms can equal or better the performance of primes at their various focal lengths.
An example is the recently tested Tokina 50-135mm f/2.8 Pro DX AF full-frame zoom (equivalent to about 75-200mm on the most popular consumer DSLRs). SQF results were Excellent at all three tested focal lengths, across the full aperture range; distortion and light falloff were very well controlled. It would be very hard to find three f/2.8 primes with that kind of performance at a budget of $700-the Tokina's street price.
But in long-lens wildlife and sports photography (and also in macros), primes still rule. While there are good, long tele zooms, above 300mm many serious shooters choose a single focal length. If you go this route, consider the 1.4X teleconverter matched to your specific lens, which gives you 40 percent more magnification with a loss of just 1 stop in brightness.