"Pancake lenses are hot sellers in the mirrorless system world but unfortunately there're only a handful avaiable for full format DSLRs. As of the time of this review only Voigtländer offers two of such lenses in Canon EF mount and today we will have a look at the Voigtlander Ultron 40mm f/2 SL II. We already reviewed the lens quite a while ago on Nikon DX but we were curious how the lens performs on a full format camera. Like all SL II lenses it is a manual focus lens but it is fully coupled so a camera-controlled aperture, focus confirmation and EXIF information are all available. The Ultron is basically a standard lens with typical applications such as street and low light photography."
Via Philippe Gassmann