Canon EF-M 22mm f/2 STM review

With a moderately wide viewing angle and fairly fast aperture, the Canon EF-M 22mm f/2 STM ticks the right boxes for street photography and everyday shooting with an EOS M system camera. As a ‘pancake’ lens, it’s just under an inch long and weighs just 105g, despite having a durable metal rather than plastic mounting plate.

Specifications

Mount: Canon EF-M
Full-frame: No
Autofocus: Yes
Stabilization: No
Lens construction: 7 elements in 6 groups
Angle of view: 63.5 degrees
Diaphragm blades: 7
Minimum aperture: f/22
Minimum focusing distance: 0.15m
Maximum magnification ratio: 0.21x
Filter size: 43mm
Dimensions: 61x24mm
Weight: 105g

Key features

Given the downsized build of EOS M bodies, the overall camera and lens combination is particularly stealthy, especially when composing shots on the rear screen rather than raising the camera to your eye. Indeed, some EOS M models don’t have viewfinders anyway. The STM (Stepping Motor) autofocus system is quick and very quiet, and manual focusing benefits from an optional focus peaking display, featured in all current EOS M cameras.

An aspherical element in the optical path helps to reduce the physical size while also boosting image quality, minimising spherical aberrations. Super Spectra coatings are also applied to reduce ghosting and flare. All that’s really missing is optical image stabilization and a hood, the Canon EW-43 slimline hood being sold separately. Even so, the design of the lens really does make the hood an optional extra rather than an essential add-on.

Performance

Sharpness and contrast are pretty respectable and our lab tests revealed the lens to be distortion-free. Vignetting is quite apparent at f/2, but mostly disappears when stopping down to f/2.8. The short minimum focus distance of just under 6 inches enables a 0.21x maximum magnification ratio and a tight depth of field for close-ups. Bokeh is pretty smooth and remains of fairly good quality when stopping down a little, although the 7-blade diaphragm isn’t particularly well-rounded.

Lab results

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).

Sharpness:

Center-sharpness is very respectable from wide-open down to f/11 but pretty average across the rest of the frame and a little disappointing at the extreme edges and corners, especially at very wide and narrow apertures.

Fringing:

Color fringing is very minimal at all apertures, even towards the edges and corners of the image frame.

Distortion: 0

Even uncorrected in-camera, our lab-tests delivered a perfect score for distortion, without any barrel or pincushion.

Verdict

Remarkably compact and lightweight, this pancake prime has a classic 35mm ‘effective’ focal length on Canon’s APS-C format EOS M system cameras. That makes it ideal for street photography and all-day shooting, with the advantage that you can shoot candidly, without drawing attention to yourself. Image quality and all-round performance are very satisfying, making it a great buy at the price.

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