The Canon EF-S 55-250mm f/4-5.6 IS STM ($349.99 direct) is a telephoto lens for Canon APS-C D-SLR cameras. It covers a field of view that’s roughly equivalent to an 88-400mm zoom on a full-frame camera, delivering impressive telephoto reach at its maximum zoom. The modest f/4-5.6 aperture isn’t the best for low-light shooting, but the light and compact design and affordable price make it a better choice for non-professional shooters. If you need f/2.8 zoom, the Sigma 120-300mm F2.8 DG OS HSM earns our Editors’ Choice with its impressive sharpness, constant f/2.8 aperture, and build quality, but it’s a hefty and expensive beast.
The lens itself measures just 4.4 by 2.8 inches (HD), weighs 13.2 ounces, and is compatible with 58mm threaded filters. It sets itself apart from Canon’s previous take on this design with an STM focus motor, which delivers smooth, silent focus when used in Live View with a compatible Canon SLR—these include the T5i, the SL1, and the 70D. Image stabilization is built into the lens, and can be turned off via a toggle switch on the barrel. There’s also a switch to move between automatic and manual focus operation.
The lens focuses to 2.8 feet; that’s not that impressive for a 55mm lens, but when zoomed to 250mm it delivers about a 1:3 magnification ratio. You can’t get as close in as you would with a dedicated macro lens, but it’s useful when you want to capture images of moderately small objects. Canon’s higher-end EF 70-200mm f/4L IS USM can only get as close as 3.8 feet, but that lens is compatible with full-frame cameras; the 55-250mm is not. A lens hood is not included; Canon prices that accessory, which blocks stray light from hitting the front element in order to improve contrast, at $29.
I used Imatest to check the sharpness of the lens when paired with the EOS 70D. There are only two real knocks on its performance: At 55mm there’s a little barrel distortion, and at 250mm the edges of the frame are just a little bit soft. Imatest shows 1.6 percent barrel distortion at 55mm, which is just noticeable in field conditions. This will cause straight lines to curve slightly outward, but can be adjusted with a quick software adjustment in an application like Lightroom if it detracts from a photo.
But there’s no arguing with the sharpness at 55mm. It scores 1,996 lines per picture height at f/4, bettering the 1,800 lines that we require for a sharp image. Performance is even throughout the frame, and you can eke a bit more performance by stopping down to f/5.6—there it manages 2,300 lines. Zooming to 100mm narrows the maximum aperture to f/5, but eliminates the distortion. The lens is still sharp at 2,077 lines; edges fall off only a bit to 1,725 lines. Stopping down just a bit to f/5.6 rectifies that—it bumps overall sharpness to 2,217 lines with edges that approach 1,850 lines.
At 145mm, the aperture still maxes out at f/5, and the lens manages an impressive 2,053 lines, with edges that just fall short of 1,800 lines. Zooming to the maximum 250mm f/5.6 setting reduces the overall resolution to 1,942 lines, thanks in part to edges that dip down to 1,600 lines. Stopping down to f/8 offers a marginal improvement at the edges, but it’s something you only need to do if you desire a less shallow depth of field. All of these numbers are impressive, especially for a lens of this size and with such long telephoto reach; you’ll get sharper, more consistent performance from the Sigma 120-300mm, but that huge lens is ten times the cost and weighs a whopping 7.5 pounds.
If you’re not a pro shooter, but want a telephoto lens with an impressive reach, the Canon EF-S 55-250mm f/4-5.6 IS STM is a solid, affordable choice. At its widest it can only capture half the light of an f/2.8 lens, and only a quarter at its maximum telephoto, which will lead sports and events shooters to pro-level f/2.8 zooms. But if you’re more of a weekend warrior and don’t need to capture fast telephoto action in dimly lit conditions, this is an impressive lens to add to your gear bag. Just remember that you won’t be able to take it with you if you eventually upgrade to a full-frame Canon D-SLR.
|Optical Zoom||4.5 x|
|35-mm Equivalent (Telephoto)||400 mm|
|Dimensions||4.4 x 2.8 inches|
|35-mm Equivalent (Wide)||88 mm|
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