Canon EF 70-200mm f/4L IS USM

Pros Optical stabilization system. Fixed aperture through zoom range. Relatively light. Sharp images.

Cons Edges soft when zoomed. Adding a tripod collar is expensive. Bottom Line The Canon EF 70-200mm f/4L IS USM lens captures impressively sharp images and is optically stabilized. It's a good option for shooters who can't afford an f/2.8 zoom.

By Jim Fisher The Canon EF 70-200mm f/4L IS USM ($1,349 direct) isn't as lauded as the company's f/2.8 IS lens with the same zoom range, but it's priced about $650 less, making it an attractive option for shooters who can live with a slower lens. It is similar in design and price to the Nikon AF-S 70-200mm f/4G ED VR lens. It's compatible with full-frame Canon cameras, and can also be used with APS-C bodies, where it acts more like a 112-320mm lens due to the 1.6x crop factor. It's very sharp across the frame at its widest focal length, but performance at the edges suffers when set to 200mm.

Like other Canon L zooms, the lens features a white finish rather than a traditional black. It measures 6.8 by 3 inches (HD) and weighs 1.7 pounds. A hood is included, but not a tripod collar. Adding one helps to better distribute weight when used with a tripod and adds $210 to the cost. It supports 67mm filters and can focus on objects as close as 3.9 feet; that's not quite macro, but you'll still be able to get fairly tight shots, especially at 200mm. The zoom ring and focus ring are both large and comfortable to adjust; the zoom ring is closer to the base of the lens, while the focus ring is near the front element.

There are a couple of toggle switches on the lens. One toggles between manual focus and autofocus, and there's also a focus limiter switch. It can limit the lens to searching for focus from 3 meters to infinity, or set so that the lens functions over its full focus range. There's also a switch to enable or disable image stabilization, and to set the stabilization mode. The default mode always keeps the lens stabilized in every direction, and the second mode doesn't try to compensate for left to right motion—necessary for shots where you pan the camera along with your subject during exposure.

I used Imatest to check the sharpness of the lens when paired with the EOS-1D X. The lens exceeds the 1,800 lines per picture height that we require for a sharp image at every tested aperture and focal length using a center-weighted methodology, but we did see some softness at the edges of the frame at longer focal lengths.

At 70mm the lens is an impressive performer all around, notching 2,415 lines at f/4, with edges that top 2,000 lines. Stopping down the lens to f/5.6 improves sharpness just a bit to 2,519 lines, and it peaks at f/8 at 2,537 lines. There is a bit of barrel distortion here, about 1.4 percent, which gives a slight outward curve to straight lines; that's a modest amount for a zoom lens, and is easily corrected in Lightroom when necessary. If you use the latest version of the software, the lens is profiled; this means that automatic corrections for distortion and falloff are only a click away.

At 135mm f/4 the lens is still sharp, 2,134 lines, but edges are a smidge soft at 1,657 lines. Stopping down to f/5.6 improves the overall score to 2,247 lines, with edges that hit 1,741 lines. Performance is best at f/8; 2,355 lines averaged across the frame, with edges that hit 1,889 lines. Distortion switches to pincushion here, where lines bow a bit inward, but it's still a manageable 1.3 percent.

When you zoom all the way to 200mm you see the weakest performance of the lens, but it's still pretty good everywhere but the edges. At f/4 it manages 1,826 lines, but edges and corners are muddy at 1,294 lines. Stopping down to f/5.6 brings the overall score up to 1,913 lines, with edges that score 1,315 lines. At f/8 you get 2,128 lines across the frame, but the edges are still weak at 1,435 lines. Distortion here is 1.9 percent, still a manageable figure. The Nikon AF-S 70-200mm f/4G ED VR delivers better performance at longer focal lengths; that lens suffers from some edge softness at 70mm, but is sharp from edge to edge at 200mm.

If you're in the market for a telezoom lens for your Canon camera and don't have the budget for the f/2.8 version, the EF 70-200mm f/4L IS USM is an appealing choice, even though its performance suffers at the edges at its longest focal length. For an extra $100 you could opt to go with the larger, heavier EF 70-200mm f/2.8L USM, but that lens doesn't incorporate any type of image stabilization—that's quite useful in a lens of this focal length. Canon's stabilized f/2.8 70-200mm zoom sells for $2,000, and is a better choice for event photographers who often need to shoot in lower light.

View the original article here