This is from Greg Erker:
Here's something that Pentax should do with the *ist lens mount (though I don't think it's likely). What made me think of it is the Olydak having a registration distance that is basically the same as 35mm SLRs. The Ist has a K-mount, so the normal K mount registration distance, but it does have (I assume) a smaller mirror. So it would be possible to make lenses that have the rear element project further into the camera. This makes wide angles less "reverse telephoto" and thus presumably cheaper to make as well as smaller (especially the front element). Now you would only do this with a reduced image circle lens so people shouldn't want to use it with film cameras. But if someone did it could cause body damage. So I was thinking the lens should have a mechanical projection on the mount that would prevent it from mounting on a normal K-mount camera. But on the Ist and future APS sized cameras they would have a cut-out to allow the lens to mount. The net result is a K mount compatible camera that has the benefit of a reduced registration distance to make wide's easier. And protection from damaging film cameras. What do you think? Regards - Greg (electronics engineer / 3d camera builder) (Share this with the PDML if you like. I'd be interested in hearing what others think.)
