Conclusion: This lens might be the best buy of the entire Canon line of lenses..I tested the canon 40mm against the 40mm f2 from Voightlander and was pleasantly surprised by the Cannon.I'm not going to say that the Canon was better in every way; but as far as center sharpness goes, I was amazed. I found my copy of the 40mm f2.8 pancake to be sharper in the center for all f stops untill f16 when Voightlander catches up. At f22 the voightlander is sharper.
Pros: Fast auto-focus, Superior build quality, Super-sharp images, price
Excerpt: I use this lens as my general all arounder for taking mostly interior shots of my family. It's great in normal/shady lighting conditions. No telephoto, so there needs to be a little distance between you and the subject. Also, AF for video not so good. Beyond that, though, it takes great portrait photos and feels like a good quality lens.<br /><br />Most important to me is the form factor. This makes my SL1 nice and compact.
Excerpt: I was looking to lighten my load and paired this featherweight lens to my 6D. I am very pleased with both the weight and the performance of this combo when I hike or trail-ride. This lens is sharp and at 2.8 it is plenty fast. I"m so glad I didn't go with a point and shoot for the trail but rather my full frame and a great lens! Great for stills and video. If you are considering getting the 40mm, just do it! Price is right and you will not look back.
Pros: Consistent Output, Fast / accurate auto-focus, Lightweight, Low profile, Nice Bokeh, Strong Construction
Excerpt: This is a nice lens. I am a big fan of the 50mm focal length for the kind of photography I do, but this 40mm is a nice compromise for when I need a wider angle but don't want to go down to 35. It's fast, accurate and responsive, and the low profile is just gravy; it's indeed much less obtrusive for carrying and for using in a more spontaneous way. Sweet bokeh as well. Very happy with this lens.
Pros: Fast / accurate auto-focus, Lightweight, Nice Bokeh, Strong Construction
Excerpt: I shoot mostly sports and use my 70-200 or 300 on my cameras most of the time but wanted a small/fast lens to get the group shots. It's a great little lens and love the fact that it takes up so little space in my bag or pocket.
Pros: Fast / accurate auto-focus, Lightweight, Small But Great Features
Excerpt: This camera lens packs one serious punch. We have previously seen from Canon another low-end product but deliver such a high and quality. I could not be more happier with this lens great product for the price.