Some of the third party K-M42 adapters stick out of the camera body,
which doesn't help lens registration much. Genuine Pen tax adapters
mount flush in the K mount and retain exact registration.
keith_w wrote:
Godfrey DiGiorgi wrote:
On Oct 4, 2005, at 9:55 AM, Mark Roberts wrote:
M42 and K-bayonet have the same register...
Lens mount body flange-to-film plane measurement?
...and very similar to Nikon
bayonet. That's why there are no adapters I know of that will allow
infinity focus.
There used to be a K-to-M42 adapter that did allow infinity focus. It
contained one or more optical elements to make this work. ...
Mark, or somebody, didn't leave his quote source intact, so I don't
know to whom I should address this question, however...
Are you telling me that when I attach Pentax' own M42 to K-mount
adapter ring to my K-mount bodies, none of the M42 lenses I
subsequently mount will actually be able to focus to infinity?!
I was rather nonplused, but managed to ponder...I think that when such
a situation occurs, I don't think I attach any M42 mount lens
specifically to take scenics or other very long distance shots, nor
did I blow any of them up to 11X14" or beyond, so I guess I never
noticed.
I think the poster is right, and *I* need to be more critical in my
examination of my images!
Perhaps I was fortunate that all settings in the past have utilized
good light, combined with mid- or small diamater apertures, so I never
noticed!
keith
It's generally a bad idea, though. The M42 mount is smaller diameter
as well as the same register which makes it hard to make this
without also putting a low-power teleconverter in such a mount.
That's what Canon did for the FD->EOS converter ... and IMO it was a
total waste of time.
I've also wondered if the lens mount casting from a K1000 would bolt
onto a Spotmatic. Those cameras were similar enough that it just might
be the case. You'd be limited to stop-down metering, but you'd have an
interesting conversation piece.
Yup. Like the guy who adapted the Leica R bayonet mount to his Nikon
F2 body. Hated the Leica R bodies, loved their lenses, and didn't
care about Nikkor lenses...
Godfrey
--
When you're worried or in doubt,
Run in circles, (scream and shout).
