Super Takumar 50mm f/1.4 vs. Pentacon 50 mm f/1.8

"Matt White" wrote in message news:lSxYe.95060

One thing to be careful of on EOS bodies (which I assume the 1.3x crop
DSLR is) is that on some wide and normal M42 lenses, the rear lens element
is so far back that the mirror will actually collide with it when it's
near or at infinity. I can't use my wide and normal super taks on my EOS
film bodies because of this. I don't know if this will happen to you, but
it's something to watch for.


Good point.

The 50mm Takumar f/1.4 normal lens was developed primarily for the Spotmatic
and ES models. The rear element tended to protrude just a tad too far back
to be compatible with other makes of camera, and more than a few users of
competing brands had their reflex mirror break, or saw the rear element of
the lens become damaged.

I have always had the suspicion that Asahi might have designed the lens that
way to discourage buyers from trying to get off cheap and mount them to
non-Pentax cameras, many of which used the Universal M42 mount back then.
Asahi made an obscure comment in their camera manuals that the 50mm normal
lens was not designed to be used on other cameras. If a customer wanted to
use what was then Asahi's flagship lens, it had to be on a Pentax camera.
As I recall, my local dealer did not even sell those lenses as stock
items--you got one with the purchase of a Pentax body, and to buy the lens
alone required a special order. It may have been that Honeywell, the
importer at that time, was trying to discourage people from trying to avoid
buying their cameras.

If anyone is in the position of wanting to mount a Takumar normal lens on
another make of camera, the simplest solution is to go with the 55mm f/1.8
or 55mm f/2.0 Takumars, which do not have that nasty protruding rear
element. They also do not have Thorium mixed into the optical glass used in
the elements, and thus have none of that pesky "yellowing" problem.