Graywolf wrote: > > The problem with interchangeable backs on 35mm cameras is not patents, but > technology. It is simply that digital sensors have not been on the surface > of the chip but buried behind a protective surface and then maybe an > antialiasing filter over that. > > What does that mean? Well, look into the back of your camera. See the shiney > rails the film rides on? Now look at the shutter curtain see how close it is > to those rails? Now the film has to ride on those rails for the image to be > in focus. If the surface of the chip is placed on the rails the actual > sensor is too far back to bring the image into focus. If you use a smaller > chip and push it down into the film aperture between the rails it interferes > with the shutter. So neither option will work. The reason they don't have > that problem with medium format magazine back cameras is that the film rails > are in the magazine a few millimeters behind the physical back of the camera > body which allows enough clearance to place the sensors exactly at the focus > point. > > Now, what seems to be the difference with the sensor for the proposed Leica > back is they have managed to place the sensors right at the surface of the > chip (actually, inset less than 7 microns). That is a major breakthrough. > However, you may have read in the article that there is no antialiasing > filter. That is simply because there is no room between the chip and the > shutter. > > Silicon film has an even more difficult problem because it has to fit > between the film rails and the pressure plate of the existing back. I would > imagine that the problem they have found insurmountable so far is making a > sensor that thin that is not also so fragile that it is useless in the real > world. > > I have explained this before, but it was probably back when we were talking > about the MZ-D which was quite a while ago.
Thanks, Graywolf, for that very informative posting. Best regards, John
