On July 23rd, 2012, Canon announced the beginnings of the EOS-M system with a new mount, two lenses, and an EF adapter.
The 22mm was the prime that Canon created specifically for the EOS-M and it was quickly a fan favorite for those that used the original EOS-M and continues to be a favorite lens today. It is a full frame equivalent 35mm focal length and extremely small and lightweight.
Canon stated back in 2012 that this lens;
The EF-M 22mm f/2 STM kit lens is ideal for shooting video and still images. The fixed focal length lens has a great capacity for gathering light with an incredible aperture of f/2 and when combined with the camera’s APS-C image sensor, provides beautiful bright images and background blur for both video and stills.
||STM Stepper motor
|Full time manual
||Graphite or Silver
The lens is a pancake lens, consisting of a metal shell and metal mount, but a mainly industrial plastic interior. The filter ring using the supplied hood is a diminutive 43mm, and it has a very small STM (stepper motor) drive for focusing.
Because of the size of the front element, the lens hood also functions as a filter adapter, providing as well an additional 43mm filter thread.
Physically, as with all EF-M lenses to date, it has a diameter of approximately 60.9mm, and a very small focus ring located at the front of the lens.
The manual focus adjustment is focus by wire, which means that electronically the lens detects if you are spinning the focus wheel and moves the lens accordingly electronically. As you move the wheel faster or slower, will depend on how quickly the focus adjustment occurs. Many people dislike this focus method because it lacks the tactile feel and consistency that you get with mechanically coupled focus rings.
The EF-M 22mm has a design consisting of 7 elements in 6 groups. Given the size of the lens, it’s a rather complex design not usually found in pancake lenses.
Summary - MTF
The MTF (or Modulation Transfer Function) provides a way to measure lens performance. Atypically this is computer generated based upon models, the lone exception being Zeiss that shows their MTF’s based upon a production lens sample.
For a detailed explanation of MTF and specifically how Canon shows their charts, refer to the article in Canon’s Digital Learning Center here.
Reading MTF Charts
The charts suggest that for a pancake lens, the EF-M 22mm will deliver good wide-open sharpness in the center, tailing off to the extremities, and very good performance stopped down to F/8.
Contrast is good for the center of the frame, and tailing off to the extremities, and as with sharpness, it improves as you stop down the lens.
Here is a sample image which you can navigate through the aperture and focal and see how our copy of the lens responds. For this example, no lens corrections have been turned on. Sharpening within DPP is left at the default of 2.
As we can see from our example, it conforms well to the MTF diagram. The corners are definitely soft wide open the lens sharpens up in the corners as you stop down the lens.
Canon’s DPP and some of Canon’s later camera bodies contain DLO, Digital Lens Optimizer, which can be used to correct various aberrations with any of the supported cameras and lens combinations. All the EF-M lenses have DLO “configurations” allowing you to further improve the characteristics of the lens. Using DLO with this EOS-M lens is highly recommended as it clears up a lot of aberrations and the resultant images are excellent. As you can see from our DLO samples below it sharpens up this lens considerably removing all traces of heavy CA.
If you are interested in learning more about DLO, Canon has a DLO mini-website, located at https://global.canon/en/imaging/dlo/
Sharpening for non-DLO images is set at USM Strength 2 Fineness 2 and Threshold 1 and for DLO images, USM Strength 1 Fineness 2 Threshold 1 with DLO strength set to 50.
We tested this lens on a full spectrum modified Canon M5. The conversion was done by Kolari Vision, who in our opinion, one of the leading vendors of infrared modified cameras and filters.
Converting your camera allows it to be more sensitive to infrared wavelengths, that are normally reduced by your sensor’s IR/UV cut filter. IR conversion removes that cut filter, and replaces it with an infrared filter, or in the case of full spectrum, clear glass. This allows the camera to be far more sensitive to various wavelengths that normally a camera is not. Because normally cameras are not sensitive to these wavelengths, lenses are also not designed around these wavelengths. Various problems may occur with complex lens designs, including hotspots (a center area of the lens brighter than the peripheral, more noticeable as you stop down the lens) and wavelength smearing which atypically shows up as a loss of resolution in the periphery of the lens. Lenses are also more prone to flare.
Each test is performed using Kolari Vision slim PRO anti-reflective infrared filters, which we find to show the best characteristics and contrast of any filters we have tried. They also have Teflon coated filter threads which we find to be extremely useful when we are swapping filters frequently during testing. While any filters will show an adequate final image, since each photo you are taking with a converted camera has a filter, we recommend using the highest of quality filters that you can afford.
A special note about the infrared test images. It's very common because lenses aren't designed to focus infrared light instead of visible light at the lenses are softer than what you'd see normally with color images. For infrared images, usually aggressive sharpening and contrast curves are used to bring out as much as possible from the image. For a good judge of the image characteristics, click on the 2:1 button to reduce the image magnification down to 50%. We usually find most infrared images look exceptional at around 50% magnification. For each image, you can download and view to your own satisfaction.
Hot Spot Performance
By around F11 a hotspot will begin to form and be distinct at around F16. If you use the lens in normal apertures at or below F8, then this lens is an excellent performer.
This lens performs well with infrared, exhibiting no long wavelength smearing or other artifacts. Resolution across the frame is excellent.
Sharpening is set to an aggressive USM Strength 6 fineness 6 threshold 2 for non-DLO images and set to USM Strength 4 fineness 5 threshold 2 with DLO images, with DLO strength set to 100.
The EF-M 22, like most pancake lenses has significant vignetting of approximately 3 stops wide open and decreases as you stop down the lens. Even by around F5.6 vignetting is still visible. While this is easily correctable, it will cause additional noise in the corners after correction.
The EF-M 22mm 2.0 at the time of this writing is the only fast prime that exists for the EOS-M system natively without using the EF adapter. It’s small, light and good optically in both color and infrared.
I’m honestly not sure about the quality control of this lens. I feel that our one of the two copies that we have tested have been sub-par.
While Canon hasn’t made many of lenses for the EOS-M system, this is one of the standout lenses that is hard to find in other competing systems, even those with far larger lens ecosystems.
When I first got this lens, I found the focal length too short, or not wide enough. As I continued to use it the more I liked it. It’s hard to find a reason why you would not add this to any EOS-M kit as a small walkaround 35mm equivalent lens.