On Tue, Jun 12, 2007 at 09:26:12PM -0400, Doug Franklin wrote: > John Francis wrote: > > > Not true. A 600/5.6 for a 1.5x crop digital will be every bit as large > > (and as heavy) as a 600/5.6 for a 35mm film camera, which in its turn > > is as large and heavy as a 600/5.6 for a medium format camera. At those > > sort of focal lengths there's plenty of image circle to spare. > > Only the first element, depending on lens design, I thought.
But there's no reason for the lens design to be any different. A design that works for 16x24mm sensors will work for 24x36 sensors (or film). There's more than enough image circle to spare, so there's no need for (or benefit to be gained from) a different optical design. And if the lens mount is the same (which it is, for a K-mount camera) then there's nothing to make two different mechanical designs necessary, either. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
