On Jul 23, 2005, at 9:07 AM, Cory Papenfuss wrote:
i think, a much cooler solution would be to
- drastically reduce the film-to-flange distance (kinda like what
oly did)
- sell a body adapter "new K"->K with the linkages and all, to be
able to use
the old lenses
- sell a T/S "new K"->K adapter
- plus adapters to all other lens manufacturers.
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.
The issue with traditional lens mounts for 35mm SLRs when being used
for DSLRs is that the mount is not large enough diameter for the lens
designs required for proper telecentricity without reducing the
format size. That's one of the reasons why the manufacturers went
with 16x24 format sensors: compatibility with existing mount and lens
designs. It's a reasonable compromise with the least cost and the
most usability Canon has been through quite a bit of development with
the largest mount diameter to fit a 24x36mm sensor.
Register distance is less critical, but the shorter the registration
gets, the less room you have for mirror mechanism. A mm or two is
enough for a mount adapter, however ... 1cm shorter is likely
impossible, mirror dimensions being what they need to be. Of course,
it also means that any "new K" lenses would be completely unusable on
the older Pentax bodies, just like it did for the Canon FL/FD lenses
when they went to the EOS mount (shorter register by 2mm or so,
IIRC). I don't think I'd like that.
Basically the "through" adapter is like a K-mount teleconverter,
but without any optics.
Then it would do nothing other than add complexity to the lens line.
I thought the notion was to try to make the old lenses image wider on
the smaller format. You can't make a given focal length lens image
differently without optics ... a 50mm lens remains a 50mm lens, etc.
So I don't understand what the point of this "reduced register"
design would be.
Godfrey
