Following are image sharpness comparisons between the Canon EF-S 10-18mm f/4.5-5.6 IS STM Lens and the Canon EF-S 10-22mm f/3.5-4.5 USM Lens. These images were captured with a Canon EOS 60D under a clear sky. Images were processed in Digital Photo Pro using the Standard Picture Style with a sharpness setting of "2" (low) and crops shown are 100% resolution. Image brightness was adjusted slightly to level all images at the same central point.
The following images were cropped from near the center of the frame. Use the links below to show the referenced image.
In the center of the frame at 10mm, the 10-18 is mildly sharper at f/4.5 and f/5.6. With diffraction starting the show its effects, the comparison at f/8 is close with the 10-18 still has slightly better contrast. At 18mm, the 10-22 has a very slight advantage at f/5.6, but any difference at f/8 is tough to discern.
Want to see the worst image quality a lens can deliver? Look in the extreme corners of the frame. In this comparison, we look at the bottom left corner of the frame. There were 64 pixels cropped off of the 10-18mm STM 10mm images to better-align with the 10-22mm images. While this could be viewed as an advantage to the STM lens, the difference was meaningless in this specific comparison.
Again click on or mouseover the links to show the referenced test sample.
The corners always bring out the worst in a lens' image quality. At 10mm, the 10-22 does not show great corner results, but the corners are looking better when stopped down to the 10-18's available apertures where these lenses perform similarly. The 10-22 is modestly sharper in the 18mm corners.
Back to the Canon EF-S 10-18mm f/4.5-5.6 IS STM Lens Review.