A couple of months ago I got a Canon EF 40mm f/2.8 STM Lens also know as a pancake lens due to its dimensions. It is a small lens which it designed for use as a video lens because of its silent motor (STM meaning stepping motor). The quality of the lens is good with the connection area being metal, instead of plastic on cheap lenses. It has a 40mm focus length which works well in both in-door and out-door situations. When videoing even though the lens it meant to be silent there is a slight noise.
The lens is very thin like a pancake and because of the dimension it easily fits into the camera bag. This is not a professional photographers review of the lens, but after using it for a couple of months I have found it a very useful lens, not just for taking video, but it produces some great photos which are clear and sharp. Because of the size and price, which is less than £200 it is a great little lens to own and would recommend it.
