Originally posted by bobva RioRico
And some folks mod their nikon DSLRs by replacing the mount with a PK. What Pervs.
Im sorry ................. Layman's terms please
glossary (in alphabetical order):
dSLRs: digital single-lens-reflex cameras
folks: people, mostly
mod: modify / alter
mount: what the lens fits onto
Nikon: a camera brand
pervs: perverts (I'm joking!)
PK: Pentax K-mount, what our Pentax dSLRs have
Translation: Some owners of Nikon (or even Canon) full-frame (FF) cameras (older ones, usually) will modify the hardware by removing the native mount (the one that's built into the camera) and replacing it with a Pentax K-mount piece. That PK mount piece might be salvaged from a wrecked old Pentax camera.
Why do this? The answer has to do with REGISTER or flange-focal distance, the distance from the lens mount to the frame (film or sensor). Register for Canon EOS is 44mm; for Pentax it's 45.46mm; for Nikon it's 46.5mm. Lenses are built with camera bodies of the same register. Longer-register lenses can fit onto shorter-register bodies AND CAN FOCUS TO INFINITY. Shorter-register lenses on longer-register bodies CANNOT focus to infinity. So I can cut a Nikon lens a little bit, and use it on my Pentax. And Canon bodies can use almost any Pentax or Nikon lenses. But Pentax bodies can't use Canon lenses, and Nikon can't use either Canon or Pentax lenses.
Canon owners who mod their bods usually do so for convenience; dedicate an old bod for fine Pentax glass, eh? For Nikon owners, it's more critical -- it's the ONLY way they can use Pentax lenses, and still have infinity focus. Well, there *is* another way, using optical adapters that change the focal length and kill image quality. Yuck.
So if you have an old extra Nikon FF dSLR and you want to use great Pentax Takumar glass on it, you do a little body-chopping. I have some nice Nikon lenses that I got cheap, so I do it the other way around: I mod the lenses. Takes about 5 minutes per lens. No big deal. Oops, someone emailed asking how to do that -- I'd better reply soon.