Canon EF-M 22mm f2.0 STM Lens Review

Announced alongside the EOS M (review) itself in July 2012, the EF-M 22mm f/2.0 STM remains one of three lenses for the system, and its only prime lens. Fortunately Canon went in a different direction than the competition when it came to the focal length and speed on offer for their mirrorless system's kit pancake lens. Whereas Panasonic, Sony, and Nikon have all made their kit pancakes f/2.8 lenses of 24mm or 28mm equivalent, Canon has produced an f/2.0 35mm equivalent.


35mm, while still somewhat wide, falls much more into the 'general usage' category than the <28mm lenses offered by the rest of the bunch. It's a great focal length for a variety of uses, like landscapes, group portraits, and even those detestable selfies. It's a great do-all lens if you're willing to stick yourself with a single focal length.

35mm equivalent focal length is great for a variety of situations, including landscapes

Protruding only 24mm from the body when mounted, the 35/2 is extremely compact, about the same size as the Panasonic 14-42 X Zoom - which is impressive. When mounted on the M, the whole thing easily fits into a jacket pocket or pair of work pants. Oddly enough Canon packed in an rather thick lens cap that adds significantly to the thickness of the camera. It's not a dealbreaker, but a nuisance nonetheless. Despite the small size and low price, the 35mm f/2 has a metal lens mount, and a metal out barrel that makes it feel much more well-built than other lenses in its price class. Also present is a dedicated focus ring, and the front element doesn't rotate, much to the delight of polarizer filter users. Less to their delight is the 43mm filter thread, an oddball size that makes it unlikely that many of you will have existing filters in that size.

The 22mm f/2 is small even compared to the EF 50mm f/1.8

What the 35mm f/2 notably lacks is a focus distance scale. This makes it difficult to set the lens to the hyperfocal distance for landscape use, instead forcing you to rely on rough estimates. Setting the lens to (or past) infinity is also a bit tricky, especially if you're using it for astrophotography, where getting stars in proper focus is more challenging than you think without AF to rely on. Minimum focus distance is only 15cm, yielding a respectable maximum magnification of 0.21x.

The 35mm f/2 uses Canon's STM focusing motor, the same type first introduced with the EF 40mm f/2.8 STM pancake lens in 2012. Following what seems to Canon's new creed of 'it's optimized for video', the STM motor found in EF lenses is slower than a USM, faster than a micromotor, and smoother than either of them. This results in much more natural looking transitions when shooting video, at the expense of speed. But when used on the EOS M the disadvantages of the STM compared to the USM more or less disappear since the body becomes the bottleneck for focus speed. In use I'd call AF 'fast enough' for most uses. Oddly enough, when using the 35mm f/2 you'll get a slightly slower framerate with servo AF compared to the EF-M 18-55.

f/2.0 allows for pleasing portraits of larger subjects

Like the ring-type USM lenses, STM lenses like the 35mm f/2 is capable of using full-time manual focus - a feature than lets you focus manually even while in AF mode. I've always found this feature handy on my EF USM lenses, as turning the focus ring on-demand is much easier than having to flip the AF/MF switch. It's especially useful if you use back-button focus, since a half-press of the shutter button won't override you.

Sadly the implementation of full-time manual focus here is rather complicated and finicky. Manual focus override can only be engaged while the shutter button is half-press (vs anytime with USM lenses), and focus is done by wire with STM lenses, so there's a slight lag between turning the focus ring and actually seeing the change on the LCD. On the bright side the manual focus ring is smooth and precise, requiring about a full turn to go from minimum focus distance to infinity.

This is about as bad as flare can get with the 22mm f/2. I've seen worse.

Optically this lens does not disappoint, delivering very good image quality even wide open and getting better when stopped down. At f/2 it's significantly sharper than the EF 50mm f/1.8 at the same aperture throughout the frame. Wide open sharpness is impressive in the centre and mid-frame, and really only starts to deteriorate in the extreme edges and corners. The same is true at f/2.8 for corners, but edges clear up drastically. By f/4 even the corner softness issue disappears and the entire frame is sharp. I don't think there's a Canon lens with better a IQ/price ratio out there.

Click for full-size

Flare is pretty well controlled in the 35mm f/2, only exhibiting symptoms in the absolute worst of scenarios. The lens' most noticeable optical flaw is the presence of purple fringing when shooting against bright backgrounds. In the corners the fringing can be fairly thick; though quite as bad as that of the Tokina 12-24 f/4. The lens shows some minor barrel distortion, but nothing serious enough to need correcting in most situations.

Purple fringing on the 22

What's good:

• Sharp even wide open
• Very compact, fits in pants pocket when mounted to M
• Solid feeling metal body
• Quiet autofocus
• Useful all-around focal length
• Incredible value for money

What isn't:

• No distance scale
• Strong purple fringing
• Unusual filter size
• Full-time manual is a pain to use

The EF-M 35mm f/2.0 STM is a fantastic lens overall, with few downsides. Even the price is reasonable, especially if you get as part of a kit with the EOS M. $250 is a small asking price for something this portable and good quality. It's a no-brainer if you have an M.

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