Canon EF-S 18-135mm f/3.5-5.6 IS STM Lens Review

Handling and features
Performance
Verdict
Specification



This lens is an update to the current Canon 18-135mm IS lens, replacing the standard focusing motor with Canon's new stepping motor technology, which promises, smoother, quieter autofocus performance, which is especially suited to recording video.

Canon EF-S 18-135mm f/3.5-5.6 IS STM Handling and features

Just like the previous version of this lens, which has been supplied as a kit with many Canon cameras to date, this lens is constructed from high quality plastics, complimentd by a metal lens mount. As it is an EF-S lens, it can only be mounted on E-FS compatible Canon cameras, like the Canon EOS 650D used for testing. The lens balances well with this camera, being just about the right weight for good handling with a relatively compact SLR body.

Autofocus is very swift and precise and virtually silent. Unlike many of Canon's USM lenses, full time manual focus override is not possible and manual focusing is performed by the focusing motor. Manual adjustments can be made in single focus mode once the lens has locked onto a target though. The manual focusing ring is quite light to operate, but well enough damped to prevent the focus ring rotating freely. A small switch on the side of the lens allows switching between manual and autofocus quickly.
Focusing is performed internally, so the 67mm filter thread doesn't rotate, making this lens ideal for use with polarising and graduated filters.

Sharp hand held images are possible around half the time at an impressive 1/20sec, which is roughly four stops slower than the usual rule of thumb for sharp images would allow.

Canon EF-S 18-135mm f/3.5-5.6 IS STM Performance

At maximum aperture and 18mm sharpness is already exceelnt in the centre of the frame, with the clarity towards the edges of the frame being not too far behind. Peak sharpness is achieved between f/4 and f/5.6 for this focal length, and sharpness is excellent across the frame at these apertures.

With the lens zoomed to 50mm, sharpness at maximum aperture remains very high, with excellent clarity being recorded across the frame by Imatest. Peak sharpness across the frame is achieved between f/5.6 and f/8 for this focal length where sharpness is excellent across the frame.

As is usually the case with zoom lenses covering a wide range of focal lengths, sharpness falls away somewhat at maximum telephoto. Still, at f/5.6 clarity in the centre of the frame is still very good, although the quality achieved towards the edges of the frame drops to fairly good levels. Peak sharpness across the frame is achieved between f/8 and f/11 at 135mm.

Resolution at 18mm

Resolution at 50mm

Resolution at 135mm

How to read our charts The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges. Averaging them out gives the red weighted column. The scale on the left side is an indication of actual image resolution. The taller the column, the better the lens performance. Simple. For this review, the lens was tested on a Canon EOS 650D using Imatest.

Chromatic aberrations are reasonably prevalent throughout the zoom range, regularly exceeding one pixel width. These high levels of CA may pose issues, especially in images with high contrast edges.

Chromatic aberration at 18mm

Chromatic aberration at 50mm

Chromatic aberration at 135mm

How to read our charts Chromatic aberration is the lens' inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software. Apochromatic lenses have special lens elements aspheric, extra-low dispersion etc. to minimize the problem, hence they usually cost more. For this review, the lens was tested on a Canon EOS 650D using Imatest.

Falloff of illumination towards the corners of the frame is reasonably well controlled. At 18mm the corners are 1.38 stops darker than the image centre at maximum aperture and visually uniform illumination is achieved with the aperture stopped down to f/5.6 and beyond. At 135mm the corners are 1.01 stops darker than the image centre and visually uniform illumination is achieved at f/8 and beyond.

Distortion is pretty well controlled for a super-zoom lens, with Imatest detecting 3.8% barrel at 18mm at 0.869% pincushion at 135mm. This level of distortion should pose few issues for general snaps, but may be too much for discerning photographers. If straight lines are paramount, then you'll be glad to hear that the distortion pattern is uniform across the frame, which should make corrections relatively straightforward to apply.

No issues with flare were encountered during testing, with only a slight loss of contrast being noticeable when shooting directly into the light at wide apertures. However, no lens hood is supplied as standard, so if you require one for peace of mind, then an EW-73B hood can set you back up to £30.

Canon EF-S 18-135mm f/3.5-5.6 IS STM Sample Photos

Value for Money

Currently, this lens is available for around £350, but the price has continued to drop steadily from launch. As the original version equipped with a standard focusing motor is currently available for over £100 less, it makes the new lens look quite expensive.

The closest equivalent from third party manufacturers is Sigma's 18-125mm DC OS HSM lens, which is equipped with optical stabilisation and a silent focusing motor for around £230.

Canon EF-S 18-135mm f/3.5-5.6 IS STM Verdict

For a lens intended to be bundled as a kit with Canon's consumer Digital SLRs, this lens performs well, providing decent sharpness, especially at shorter focal lengths. The inclusion of image stabilisation is a bonus too and the system works effectively.

Good as the STM focusing motor is, it isn't quite a revelation in terms of performance or usability. If one was shopping for a lens covering this range, they may do well to look at the older version for now, while the price gap is so large.

Canon EF-S 18-135mm f/3.5-5.6 IS STM Pros

Good sharpness for a superzoom
Lightweight
Fast focusing
Effective stabiliser

Canon EF-S 18-135mm f/3.5-5.6 IS STM Cons

High CA levels
Overpriced when not sold as part of a kit

FEATURES
HANDLING
PERFORMANCE
VALUE FOR MONEY
OVERALL

Canon EF-S 18-135mm f/3.5-5.6 IS STM Specifications

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