Designed for APS-C format DSLRs, the Canon EF-S 55-250mm f/4-5.6 IS STM can also be used on both APS-C format and full-frame mirrorless EOS M and EOS R system bodies, via their respective EOS mount adapters. Larger and heavier than the Canon EF-M 55-200mm f/4.5-6.3 IS STM, this one has more traditional DSLR-type styling, with physical switches for AF/M focusing modes and stabilization on/off, as well as chunkier rubberized grips for the zoom and focus rings.
Mount: Canon EF-S
Lens construction: 15 elements in 12 groups
Angle of view: 27.8-6.25 degrees
Diaphragm blades: 7
Minimum aperture: f/22-32
Minimum focusing distance: 0.85m
Maximum magnification ratio: 0.29x
Filter size: 58mm
Although nearly 50 per cent heavier than the Canon EF-M 55-200mm f/4.5-6.3 IS STM, the EF-S model adds an extra 50mm in telephoto length, with an overall zoom range that’s equivalent to 88-400mm in full-frame terms. It also has a slightly faster aperture rating, shrinking to f/5.6 rather than f/6.3 at the long end. Similarities between the two lenses include fast and virtually silent stepping motor-driven autofocus and 3.5-stop image stabilization. Both also have weight-saving plastic mounting plates, which should prove sufficiently robust but aren’t as durable as metal mounts.
Compared with the previous edition of the EF-S 55-250mm, the new version has a more complex optical path with three extra elements, including the addition of a UD (Ultra-low Dispersion) element. This aims to reduce chromatic aberrations while boosting sharpness and contrast. The basic electric autofocus motor of the previous edition was much inferior.
Levels of center-sharpness are pretty good throughout most of the zoom range and sharpness generally holds up quite well towards the edges and corners of the frame. There’s very little in the way of color fringing and distortions are pretty low as well. Overall, this lens is a solid performer that’s well matched to Canon’s APC-S format DSLRs - and its focal range makes it a perfect partner to the Canon EF-S 18-55mm f/4-5.6 IS STM kit lens.
We run a range of lab tests under controlled conditions, using the Imatest Master testing suite. Photos of test charts are taken across the range of apertures and zooms (where available), then analyzed for sharpness, distortion and chromatic aberrations.
We use Imatest SFR (spatial frequency response) charts and analysis software to plot lens resolution at the center of the image frame, corners and mid-point distances, across the range of aperture settings and, with zoom lenses, at four different focal lengths. The tests also measure distortion and color fringing (chromatic aberration).
Center-sharpness is pretty respectable, only dropping off a bit in the shorter section of the zoom range when using the widest available apertures. Mid/edge-sharpness is less impressive at the shortest focal length.
There’s fairly little in the way of color fringing at almost every combination of focal length and aperture setting, with the exception that it can be quite noticeable when shooting wide-open at 250mm.
When uncorrected in-camera, barrel distortion can be slightly apparent at 55mm for there’s comparatively little pincushion from 100mm onwards, as you extend through the zoom range.
With a new and improved optical design and a faster, near-silent autofocus system, the ‘IS STM’ edition of this lens is much improved compared with the original version. Designed for Canon’s APS-C format DSLRs, it’s quite compact and lightweight, yet offers a useful ‘effective’ zoom range of 88-400mm in full-frame terms. All in all, it’s a good telephoto zoom if you like to travel light.