On June 6th, 2013 Canon announced the forth lens in the EF-M ecosystem, the EF-M 11-22mm 4-5.6 IS USM. This lens features an equivalent to full frame focal range of 18mm to 35mm and provides an ultra-wide lens solution for the EF-M ecosystem.
Canon had this to say when they released the lens;
Designed to expand the range of creative possibilities and shooting subjects, the EF-M 11-22mm f/4-5.6 IS STM has an 11-22mm focal range which provides an incredibly wide field of view. This allows users to capture the environment around them whilst remaining close to the subject – ideal for adding drama and atmosphere to each shot.
|CIPA IS rating
||2 aspheric elements
||STM Stepper motor
|Full time manual
The lens is a very compact lens for an ultra-wide zoom.
The lens has a switch to extend the lens from its unused retracted position. It is mandatory that you switch and zoom the lens out to at least 11mm to use the lens. An EOS-M camera will present you a warning if you do not do this step.
The lens sports a metal mount, and when extending the lens, the barrel does not wobble due to a good build quality and tight tolerances.
The STM motor used in this lens is a lead screw STM motor and offers fast AF.
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 optical design is 12 elements in 9 groups that supports a minimum focus distance of .15m which allows for an excellent .3x magnification.
The 11-22 smoothly increases from 4.0 to 5.6 from 11mm to 19mm while at 19mm it stays at 5.6 to the end of the zoom at 22mm.
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 wide angle lens, the EF-M 11-22mm will deliver good wide-open sharpness in the center, tailing off to the extremities, and very good performance stopped down to F/8. The lens will increase in overall sharpness in the corners as you stop down, and also as you increase focal length. Center sharpness is excellent throughout the zoom range.
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.
As we can see from our example, it conforms well to the MTF diagram. The corners are good wide open the lens sharpens up in the corners as you stop down the lens. Center performance is excellent throughout the zoom range.
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 CA especially at 11mm.
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. Depending on your filter choice, there's also a lot less RGB pixels receiving light, therefore, less sharpness. For infrared images, very 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
The EF-M 11-22 exhibits hotspots at smaller apertures. At 11mm through 14mm we see a hotspot slightly forming at F11, whereas at 17mm and up to the end, 22mm hotspots are barely distinguishable at F22.
There's a lack of contrast visible at the lower focal lengths, and when the lens is wide open. There is obvious smearing on the edges of this lens as well, especially with filters less than 850nm. The center performance is excellent. Images shot with 850nm stopped down to F/8 are excellent. This lens can be used for infrared IF you are aware that the edges will smear, shoot 850nm, or you simply limit your print / viewing to around 50% of magnification.
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 11-22 has heavy vignetting wide open at 11mm of around 3EV and decreases as you increase both the aperture and also the focal length.
It’s extremely hard to find fault in the EF-M 11-22 given it's size, weight and relatively inexpensive price. Perhaps if you are using it for infrared it may not be the best lens out there, however to be fair, it’s difficult to find modern ultra-wide lenses that behave well with infrared. Even with that, for most use cases of the EOS-M system and even infrared the lens is acceptable if you take the sides into account when you are shooting. For color photography there is little to complain about, except vignetting at 11mm.
This is certainly a standout lens for the EF-M system especially when you consider the excellent price. Price performance ratio for this lens is extremely high and it’s certainly a lens that deserves to be in every single EOS-M system kit.