Review on Canon EF 40mm f/2.8 STM Lens - Fixed Black (6310B002) for US Cameras by Dimitar Konstantinov ᠌

noise during manual focusing can be avoided by smoother rotation of the ring (not always acceptable, but the feeling that the STM seems to resonate with fast refocusing) Different pros: weight / size, price, quality of the picture immediately from 2.8, uniform focus over the entire field Cons below: noise during manual focusing (for video, it can be critical), the "trunk" must be protected from being pressed (it can jam when the cover is installed, after restarting the camera it is restored, there is even a technical note from Canon)