From Roger at LensRentals.com
As Roger does, he received the new Canon EF 40mm f/2.8 STM lens and had to immediately put it through the paces.
Roger did some computer aided tests to check the sharpness at MTF 50 and compared it with other higher end Canon zoom lenses, and it turns out the little pancake outperformed them in some areas.
Overall, though, I’m extremely impressed. I’d be impressed if a lens this size and price was just decent, but this one is excellent. I might as well go ahead and get in trouble with the business manager: if you think you want this lens, just go ahead and buy it. At this price, unless some of the more thorough reviewers find something I missed on this quick overview, you can’t go wrong.
Read the entire review at LensRentals.com here.