I've owned a 500C for a number of years, and use it primarily for photographing landscapes and interiors of houses. For rooms I tend to use a 40mm Zeiss Distagon, which I love. It's just a beautiful lens, really sharp but still rich and warm. Invariably, when photographing a whole room, the challenge is to get as wide an angle as possible without any fisheye distortion. For this reason my attention has been drawn to the 38mm Biogon SWC. I'd be very interested in hearing from anyone who's had experience using these two cameras side by side, ideally in this context. Does the 2mm make a big difference, and are there any other pros/cons of the Biogon? The advantages would have to be significant, because I really don't like the idea of looking through a viewfinder as opposed to the lens, even though I know focussing isn't such a huge issue here. I understand why the Biogon can't be mounted to an SLR body, and I am also intrigued by the idea of Hasselblad accepting a lens design that refused to compromise itself to the dictates of the overall system. It must have had something going for it to have got away with breaking all the rules! Any more thoughts on this one-off would be most appreciated.