I love seeing how things work inside, and LensRentals pulled apart some pancakes for exactly that reason. The lenses under the knife are the Olympus :43: 16mm and Sony NEX 16mm pancakes. Lots of really cool pictures. One of the cool things is that the Oly 17mm has no focus element. In order to focus, the entire lens is shifted forward or back -- which explains the poor focus speed, I have to say.