Hi Moose, Chuck and all,
From: Moose <olymoose@xxxxxxxxx>
>> I'm an OM lens fan, they have excellent performance.
>
>Many of them do, especially the later ones. The early 50/1.8 I got with my
>first OM-1 was significantly softer than the Nikkor 50/2 it replaced.
Yeah, I got that Nikkor-H·C 50/2 and it's really nice! In my experience,
Nikon lenses usually make nice-looking pictures, but rarely outstanding.
Most of the time I get better performance from Zuiko lenses, the 50mm being
the notable exceptions -- those 50mm Nikkors are very sharp even wide open,
if a bit harsh.
>The big negative is the aperture mechanism. Even a genius
>like Maitani can make mistakes. The decision to drive the
>normally open aperture closed against a stop at an unknown
>(to the camera) location against a spring of unknown strength
>was such a mistake. It requires strong radial motion that
>bangs against the stop. That's true even with a small lens
>with light aperture mechanism and spring, as it has to also
>be able to drive the big ones.
>
>The Nikon design, with a normally closed aperture, held open
>by the camera when the lens is mounted, is inherently lower
>vibration. The camera just gets out of the way of the lens
>closing it's aperture. No big bang from the camera mechanism.
I thought about this after waking up on my last day of holidays... I think
you're right (I've got no dynamometer, but the stopdown lever *feels*
stiffer on the OM-1 than on the Nikon FE) although it may not be the only
reason behind:
-The OM stopdown lever moves upwards, just like the mirror, while the
Nikon's moves in *opposite* direction, sort of balancing its motion.
-Other mounts (M42, Canon FD and maybe others) use 'normally open' lenses,
just like the OM, and such complaints aren't heard about them.
-The sheer mass of most classic SLRs compared to the OM-System could be a
great damping factor -- and a possible explanation to the line above.
-"Classic" OMs (1/1n/2/2n) are among the *fastest* (low shutter lag) SLRs.
There's usually a trade between smooth operation and low shutter lag -- the
Minolta XD series, Leica R4-7 and many modern/AF SLRs being at the other end
of the scale. It's a proven fact that the OM-2S, with a different stop-down
mechanism and a *much longer* shutter lag, is the smoothest OM out there...
>Even so, the manual mechanism on the F bodies (at least
>through F2) both locks up the mirror and closes the diaphragm,
They do, at least up to the F4, AFAIK. But there's a big difference between
the system used on the original F and the one on its successors: the F2-F4
simply lock up the mirror while keeping the lens stopped down (like DOF
preview), whereas the F has a surprisingly cumbersome system that means
wasting one (or two!) frame in order to use it, but in fact *disengages* the
whole auto-iris mechanism, actually turning the F back into the rangefinder
S-series from which it derived ;-)
I have checked the MLU system of many classic pro-SLRs, and the F is *way*
smoother than the rest -- even smoother than a Bessa rangefinder! On the
other hand, on other SLRs a *slight* movement of the (already moved)
stop-down lever could be felt, along with a small shock from the mechanism
inside...
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx
>Did anyone other than Olympus use OTF exposure control?
>I believe Olympus purchased rights to use it from Minolta
>but don't know if Minolta or any other company actually
>used it themselves.
AFAIK, only *two* non-Olympus cameras used OTF for normal, non-flash
exposures:
-The Minolta CLE, a small rangefinder in Leica-M mount -- derived from the
even smaller, mechanical Leica CL. Unfortunately, it's *very far* from the
amazing low-light metering performance of "our" OMs... maximum exposure
times are rather short, especially above ASA 800. But otherwise it's a
lovely tiny camera ;-)
-The Pentax LX, a full featured pro-SLR, this one with low-light
performance comparable (if not better) to that on the OM-2. That camera was
*very* interesting, like a compilation of features from the best cameras
but, like everything Pentax, its ergonomics/design didn't fit my hands/way
of thinking, so I sold mine long ago :-(
Cheers,
--
Carlos J. Santisteban Salinas
IES Turaniana (Roquetas de Mar, Almeria)
<http://cjss.sytes.net/>
--
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