At 9:54 PM +0100 1/1/06, [EMAIL PROTECTED] wrote:
Hi,
I have holliday right now so time to think .....
my question has a high "freak" score .... you
are all warned ...
I own a Bronica S2A with some Nikkor lenses. The
S2A has a Bronica S2A bayonet & 57×1 thread with
a 101.7
register (thank you Willem Jan).
Thus if I buy a 58mm Lens Reverse mount adapter
and let a mechanic make a 57x1 to 58 mm adapter
I could
use all my Bronica lenses on my EOS and still focus to infinity. Right?
Not necessarily. The Bronica lenses, in
particular those shorter than 75mm, are
retrofocus to allow room for the mirror _behind_
the lens. Reversing the lens will negate that,
and you will find that the register of 101.7mm is
on the wrong side. You will not be able to focus
to infinity.
Would this be any usefull? Or is the resolving
power of these 30 year old 6x6 lenses much lower
as of Canon
gear. What focal lenght would a 40 mm 6x6 lens have on an EOS XT?
40mm is 40mm is 40mm. On an XT the lens would
have an angle of view like any other 40mm; ie,
slightly narrower than 'normal'.
Now the other side around. I have some nice EOS
lenses wich I think the are good optical
quality. When I look at
my 40 mm Nikkor 6x6 lens I'm astounished that
the the diameter of the glass is so small. I
expected these
lenses wider because the have to spread the
light on 6x6 film behind them .... this made me
think, some of my
EOS lenses have wider glass ....
Glass diameter isn't an indicator of much other
than complexity of construction. Canon lenses are
designed to cover a circle of 44mm or so at
infinity, except for the TS lenses, which cover
about 65 or so. Some tele lenses might cover a
lot more, but the barrel is shielded to not allow
that, because the extra angle of view would
produce a lot of non-image forming light that
will cause flare and reduce contrast.
Since the Canon lenses would be only useful for
close-up stuff and would only be used for such,
they will actually all cover 6x6 film at 1:1 when
the lens is moved one focal length further away
from the film plane than when it was focussed at
infinity. At 1:1 they will cover twice the
diameter they would at infinity, namely
One of the best setups I used for micro
photography, in this case about 10:1, was using a
reversed 13mm f/0.9 Switar from a Bolex 8mm movie
camera reversed on bellows. Great optical
quality, and actually bright enough to see
something.
Could I use EOS lenses on my Bronica? Probably
because of the film to lens distance I can't
focus to infinity. But
focus on short distance??? Or does the wide of
the glass has nothing to do with it and is
everything tuned by
different glass elements in the lens?
If it would work I could get a plastic lenscap
and fix this together with a 57x1 thread.....
Thanks!
Leeuwtje
--
* Henning J. Wulff
/|\ Wulff Photography & Design
/###\ mailto:[EMAIL PROTECTED]
|[ ]| http://www.archiphoto.com
*
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