Standard, 35mm to 135mm Leica M or LTM lenses won't work on any Pentax
film SLR or digital SLR. Mounting them is the same as putting them on
an extension tube, because they're further away from the film or sensor
plane. They'll focus nicely for macros but won't focus at distance. The
only adapter I know of that will allow use of these lenses is an LTM to
M42 adapter. It was originally intended to mount SLR lenses with 39mm
(LTM) thread on cameras with the M42 universal mount. By combining one
of these adapters with a Leica M to LTM adapter and an M42 to Pentax K
adapter, one can mount a Leica M lens on a Pentax K bayonet. But, as I
said, it will be too far away from the image plane, so it will be the
equivalent of using an extension tube. Close objects can be focused on,
distant objects cannot be brought into focus.
Paul
On Feb 11, 2006, at 1:27 PM, Shel Belinkoff wrote:
Hi,
I somewhat understand what you're saying, but not with 100% clarity. I
always have difficulty understanding descriptions of mechanical things
unless I can actually see them for myself. Once I do, everything falls
into place and becomes quite clear. Having thought about this a bit,
it
may be that Juan was talking about using a Leica (RF) lens on the
istD, not
a Pentax film body. That way the smaller mirror of the istD would
allow
the lens to fit closer to the film plane. Am I misunderstanding what
you're saying?
Anyway, I found what I believe is the adapter Juan has, and I may just
go
ahead and order one and see how it works with my Rangefinder lenses.
Then
I'll both understand what you're describing and will know for 100%
certainty what works and what doesn't.
And just to reiterate, I could very well be mis-remembering what Juan
said.
Shel
[Original Message]
From: Godfrey DiGiorgi
It would be doable with a Leica R lens, or a longer focal length
Leica RF lens with short mount and Pentax M42 adapter.
The Leica R cameras have a deeper register than the Pentax M42 and K-
bayonet mount so a mount adapter could be constructed easily enough
if the flanges and aperture actuators, etc, are not placed with too
much interference.
Leica RF lenses are designed for a much thinner mount register and
could not be adapted to Pentax without optics, unless you use a short
mount lens (designed for bellows/reflex housing) and build a custom
short mount with a Pentax end.
Godfrey
On Feb 11, 2006, at 7:35 AM, Paul Stenquist wrote:
Please report back. If there's a way to achieve this, it flies in
the face of both the physical evidence and my personal experience.
Paul
On Feb 11, 2006, at 9:59 AM, Shel Belinkoff wrote:
My memory of a discussion about this with Juan suggests otherwise
- but, I
could be mistaken. I'm looking into the issue now.
Shel
[Original Message]
From: Paul Stenquist
Unfortunately, there is no way to enable infinity focus with a
Leica
rangefinder lens on a Pentax SLR. The lens will hit the mirror if
it's
mounted close enough to allow infinity focus.
