On 16/3/05, jtainter, discombobulated, unleashed: >Somewhat more serious speculation: What if there was an adapter to use 35 >mm lenses on the 645D with full functionality,
Bad news Joseph. An adapter would be impractical - the Pentax K mount register distance (back of lens - to - film/sensor plane) is 45.46mm and the Pentax 645 register distance is 70.87mm. To use a (simple) fabricated adapter, the distance for the camera register has to be greater than the distance for the lens register - basically you are moving the lens further away from the camera, with a suitably thick mount in between. Clearly, this is not the case using K mount lenses on a 645 body. For this, an adapter containing optical element(s) would be needed to rearrange the point of focus (the back focus - yes! it exists) and you're now talking lots of money and losing quality through yet more glass. The only way would be to mount the 35mm lens *inside* the 645 lens throat, so that the distance from the back of the K mount lens to the 645D's sensor was 45.46mm - but sadly wew then have the problem of the 645D's mirror hitting the whole kit and caboodle. And we still haven't even begun to consider the fact that the image circle would be smaller than that produced by a 645 lens. Sorry mate, I love all this shit. HTH Cheers, Cotty ___/\__ || (O) | People, Places, Pastiche ||=====| http://www.cottysnaps.com _____________________________
