The 40mm is always ready for use, it is so thin it is almost a mirror cover, but whip it out and snap snap away, yes it may not be the best lens in canons line up, but sheer conveinence it wins hands down. It has good bokeh and can get quite close to a subject without distortion of the lines.

Canon is the only major Japanese camera manufacturer who has been shy of entering the mirrorless market (as of the time of this review). So far their reps always argued that it is possible to design smallish APS-C DSLRs that are also able to compete on the size and weight side.

I bought this lens to go with the RP body (with adapter). Lens and adapter is shorter/smaller than the smallest RF mount lens offered presently. RP hasnt arrived yet, but on my 5DmkIII Im getting results far beyond the price of the lens. Almost perfectly sharp, corner to corner, wide open.

I should say this is a great value for what it is: a sub-$200, fast 40mm EF lens with well regarded sharpness stats even wide open. Where the EF 40mm f/2.8 STM is a huge letdown is in the realm of video. There is distinct and audible autofocus hum that is recorded on your video.

A low-profile lens for street photography, suited for full-frame cameras...

Extremely slim and lightweight; Excellent optical quality

Unsophisticated focus system; Thin manual focus wheel

I can't believe how long it took me to purchase this lens. This review is for full-frame use. I've been rolling my eyes at it ever since it first came out. How can this lens be any good Recently reading various technical reviews raised my eyebrows and quickly changed my opinion of this lens.

Bought for my 6D so I could take it to work, have a compact light package but still being full frame. People might sniff at the fact the lens is only 2.8 but for most every day uses this is all you need.