----- Original Message -----
From: "Cory Papenfuss"
Subject: Re: "crazy" idea for more utility out of old glass on 1.5x DSLRs
Lots of problems.
- How do you drive the older lenses mechanical linkages?
- More optics in the path means performance degradation.
- Reduced room for an adequate mirror, etc with the "new K" standard
lenses.
He suggested changing the registration distance to more match the smaller
sensor. That's a good idea. Basically the "through" adapter is like a
K-mount teleconverter, but without any optics. It would probably be about
1 cm thick. So:
- Don't lose the ability to drive older mechanical linkage lenses
- Have no additional optics in the path
- Possibly... I haven't thought completely through that part, but as a
knee-jerk it seems like it should work. Nothing magical about 35mm as an
SLR.
Yer adaptor would have to have optics. The flange to focal plane distance is
part of the lens design. If you change one, you have to either change the
other (not possible), or put an optical correction in the path to make the
short back focus you have imposed on the lens possible.
William Robb
