Canon EF-M 22mm f/2 STM
Lab Test Results
February 17, 2013
by Andrew Alexander
Canon announced its EOS-M mirrorless camera in July of 2012, and the EF-M 22mm ƒ/2 STM was one of two lenses to be released with it.
The 22mm ƒ/2 was designed specifically for the EF-M lens mount, and is incompatible with other Canon bodies. The EF-M mount is designed around an APS-C sensor: in 35mm film terms, the effective field of view is approximately 35mm. Be sure to check out our review of the EOS-M at Imaging Resource.
The lens does not ship with the EW-43 lens hood - this is an optional accessory that retails for around $25. The lens itself is available now for around $250, or as part of a EOS-M camera kit.
The Canon EF-M 22mm ƒ/2 STM provided surprisingly sharp results. When used wide open at ƒ/2, there is some corner softness to speak of, but the majority of the frame is very sharp. Stopping down to just ƒ/2.8 provides very sharp images - for practical purposes, we would say it's tack-sharp from corner to corner. According to the raw numbers you'll have to stop down to ƒ/4 to see the sharpest results, but to the naked eye I doubt you would see the difference.
The lens is sharp all the way to ƒ/8, where diffraction limiting begins to set in, but there isn't a significant impact on sharpness until ƒ/11, and even then it's just a slightly overall decrease. Images start to lose their sharpness at ƒ/16, and become moderately soft at ƒ/22.
While our testing software gives the 22mm ƒ/2 a passing grade, we note some obvious chromatic aberration present in the extreme corners of the frame at the ƒ/2 setting (take a look at our sample images for further detail). In the center of the frame, it's not an issue. Stopped down to ƒ/8, it's less prominent but still visible in the corners: again, the center of the frame is fine.
There is some significant corner shading with the 22mm ƒ/2: used at the ƒ/2 setting, the corners show up a full stop darker than the center of the frame. This is alleviated as the lens is stopped down, but at ƒ/4 and smaller there is still at least a half-stop of corner shading. It's worth noting that our still life shots (found in the sample images) are done with default settings, which means that the Peripheral Illumination is enabled, so you can see how the camera can correct for corner shading.
The 22mm ƒ/2 provides excellent resistance to distortion (or, the EOS-M camera is doing some fine correction); there is no distortion to be had with the lens.
Canon employs a STM motor on this lens, providing near silent operation. Unfortunately it's not especially speedy, taking well over a second to go through its range of focus.
The lens, while not specifically built for macro, offers some usable close-up capability. Maximum magnification is 0.21x, with a minimum close-focusing distance of around six inches.
Build Quality and Handling
The EF-M 22mm ƒ/2 STM lens is small and light (105 grams, 3.7 oz): it comes finished in a nice gray color. The small size of the lens allows you to put this lens and camera combination in a large coat pocket, providing you with a higher-quality point-and-shoot alternative.
The lens has seven elements in six groups, with one aspherical element, and has a rounded aperture with seven blades. There are no switches or control surfaces other than the manual focusing ring, so its simple design matches nicely with the EOS-M.
The focusing ring is a scant 1/8'' in width, plastic with a cross-hatched pattern for texture. The focusing design is electrical, so the ring will turn in either direction without stopping. There is a little bit of lens extension as the lens is focused: it will extend by around a quarter of an inch. The front element (and any attached 43mm filters) will not rotate during focusing operations.
The optional EW-43 lens hood is available for the lens, but does not look to provide a huge amount of shade for the lens.
There aren't a lot of alternatives at the time of writing, owing to the young age of the EF-M mount.
Canon EF-M 18-55mm ƒ/3.5-5.6 IS STM ~$300
We haven't yet tested this lens, but plan to do so in the near future.
For a small and relatively inexpensive lens, the Canon EF-M 22mm ƒ/2 STM provides an excellent result. Given the few options available (as of February 2013) for Canon EOS-M users, having this prime lens as an option is a no-brainer.
The VFA target should give you a good idea of sharpness in the center and corners, as well as some idea of the extent of barrel or pincushion distortion and chromatic aberration, while the Still Life subject may help in judging contrast and color. We shoot both images using the default JPEG settings and manual white balance of our test bodies, so the images should be quite consistent from lens to lens.
As appropriate, we shoot these with both full-frame and sub-frame bodies, at a range of focal lengths, and at both maximum aperture and ƒ/8. For the ''VFA'' target (the viewfinder accuracy target from Imaging Resource), we also provide sample crops from the center and upper-left corner of each shot, so you can quickly get a sense of relative sharpness, without having to download and inspect the full-res images. To avoid space limitations with the layout of our review pages, indexes to the test shots launch in separate windows.
Canon EF-M 22mm f/2 STM
Canon EF-M 22mm f/2 STM User Reviews
9 out of 10 points and recommended by PhilUKNet (8 reviews)Small form factor, light, fast accurate AF, great image quality43mm is an unusual filter size
Some people swear by fast prime lenses, such as this one. The big aperture enables fast shutter speeds and ISO is kept lower in low-light situations. However, I actually find the EF-M zooms (18-55mm and 11-22mm) more useful in most situations.reviewed March 30th, 2015 (purchased for $215)
The EOS M system is small - I usually carry the EOS M body, one zoom lens and the 90EX flash in a small LowePro case - but when I want the smallest possible configuration I opt for this lens and leave my 90EX at home. The EOS M body with this lens attached can be stored in a small pouch designed for a 100mm lens and fastened to my belt. It's extremely light and compact.
As with all the EF-M lenses the image quality is excellent. I noticed on the review here that vignetting was described as a problem, but I leave the Lens Aberration Correction options enabled on my EOS M and this fixes any problems. If I were to shoot in RAW I would problem notice some vignetting, but I don't.
There was a time when I would have said that IS is completely unnecessary on a 22mm lens, but when switching between this lens and the EF-M 11-22mm f/4.0-5.6 STM IS I do notice the difference. IS would be useful, but it's not completely necessary and the addition of IS would probably have made the lens bigger.
Focusing is fast and accurate, image quality is good and sharp with great colours and contrast, and it comes in a tiny, inexpensive package. All told, it's a great little lens. For more of my thoughts, impressions and some sample images, see here:
10 out of 10 points and recommended by ysoli (2 reviews)Very small, has f2 aperture, very high quality lens and it's dirt cheap!Not IF, but it's not a big problem
I can't believe this lens:reviewed March 6th, 2014 (purchased for $140)
It's really small, dirt cheap, has a very good construction, and it makes impressive images!!
Optically I think it's better than the Oly 17mm f1.8, and it's price is just less than the quarter of it! And on top of it it's even smaller!
If it had internal focus, would be even better, but I still think this lens is perfect!