One of my good sources explained why the new Zeiss 24mm f/1.8 lens is so large: “The large lenses have optics that are usable, with minimal modification, with SLT cameras. NEX-7 is a high quality photographic tool. Shorter size lenses would have very short distance of the rear lens element to the film plane. With small exit lens on wide lenses there would be too much light fallout. That is why a high quality WA lens needs to be bigger. The problems with NEX system. Very short flange distance is excellent for making inexpensive, quality, small WA lenses. The problem is light fallout at the edges of the picture – because the exit pupil of the lens would be too small and close to the CMOS. It is the reason the new 24 mm Zeiss is so big.”
Reminder: The Zeiss will cost around $999 and it will have a 16cm close focusing distance.