The back element of the Pentax lens would have to "enter" inside the
Nikon mount 1 mm, and could be hit by the mirror. A non-auto Pentax
tele lens could be grinded 1 mm and no element or mechanism would be
near the mirror.
Minolta lenses are 1 mm away from Pentax, and the same can be done
for a few of their lenses.
I have a Rokkor 250mm mirror lens on my desk, its mount taken out,
waiting for a grinding session. I need to make a grinding plate with
a 39.Xmm hole in the center to gring the back "plate" of the lens,
around a fixed element (protected by a 39mm back filter). I had
previously taken out the metal Minolta mount by unscrewing it from
the inside of the back plate.
The grinding will give me about 0.7mm before I hit the screws that
hold the back plate with the lens element. It is enough as this lens
focuses past infinity.
The internal diameter of the K mount adapter being just over 39mm, I
will afterwards epoxy one on the back plate. I'll use the tiny
250mm lens on the D...
The Rokkor 500mm miror lens (same as the Leitz one) can be used on a
K mount camera without grinding because it is already focusing way
past infinity (that could change with temperature but it works in
summertime). The lens has to be hold by hand on the K mount body...
I'd like to put a K mount on it but, contrary to the 250mm, the metal
mount cannot be easily taken out. So I stopped the project... But I
have taken pics with it on the D!
Andre
On 6/10/05, Lucas Rijnders, discombobulated, unleashed:
Sorry: still confused... To quote from your resource:
"For an adapter to slip in between the body and lens of differing
manufacturers, the registration distance of the lens must be greater than
the registration distance of the body"
In this case, the registration distance of the lens (45,46mm) is _smaller_
than that of the body (46,50mm). So it wouldn't work. I think. Or, I think
I think...
Now you're getting me confused ;-)
For an adapter (without lens elements) to work, the register distance of
the body *must* be less than the register distance of the lens.
EOS register: 44mm
Pentax register: 45.46mm
Nikon register: 46.50mm
Oh God.
You're right.
And so was I when I posted:
------------------------------
On 5/10/05, Herb Chong, discombobulated, unleashed:
i wish i could mount the
Limiteds on the body and use them. Nikon doesn't have anything equivalent to
the 31 Limited.
Pentax register: 45.46mm
Nikon register: 46.50mm
1mm out!
and going the wrong way. Well if I couldn't mill 1 mm off the back of a
Limited, and stick a Nikon flange on, my name's not Dr Frankenstien.
