Ken wrote
>
> Olympus OM system had one failing. No F1.4 glass in wide and telephoto
> lenses. The F2 glass was probably a good compromise, though, and
> didn't push the mirror-chamber vignetting issue very much.
For once I disagree. The OM system has one huge failing other than the
f/1.4 one (which never bothered me as I don't ever need such fast lenses - I
had never considered that such a small incremental f-stop increase was/is a
failing or important), and their engineers failed perhaps to even recognise
that it exists, let alone do the radical redesign that was and is required.
As shown so clearly by Gary Reese in his comprehensive tests of lenses,
using several OM body designs, the vibration induced in the Zuiko lenses by
the aperture stop-down system was/is so bad as to quite undermine the
excellent optics. If you are not familiar with this series of tests, look at
the
LHS menu at Ken's site http://zone-10.com/cmsm/ and you will find one
version of it there. Take a good look.
This fact became even more evident when Canyon digital photographers
found that manual Zuiko lenses delivered excellently sharp images, and
started buying up the more exclusive versions. Their cameras do not (as I
understand it) use the aperture stop-down system that is incorporated in the
Zuiko lenses. Prior to this happening, I was not fully aware that the Zuiko
lenses are all that sharp.
As it is, to get the maximum resolution from manual Zuiko lenses when
mounted on Olympus film camera bodies, it is necessary to use a tripod,
and one of the cameras (such as the OM2000 and the OM 4Ti) which has a
shutter-delay timer which incorporates pre-fire mirror raising AND aperture
stop-down, for a long enough delay period for the vibrations induced within
the lens by the shutter stop-down system to decay down to a level that has
negligible effect on image sharpness.
What manufacturer would knowingly create a system with such a severe
design flaw?
As I understand it, other film-camera systems such as Nykon carry out the
aperture stopdown in such a manner as to not set up image-destructive
vibrations in the camera-lens system.
In my opinion, this one failing was by far the major Achilles Heel of the OM
system.
I often wondered why my carefully made hand-held Olympus OM shots did
not match the sharpness of those made by people using other makes of
camera, and it took Gary Reese to provide the explanation.
Along with this, the lightness of the OM bodies, vaunted by Olympus as an
advantage, actually worked against image sharpness when combined with
the Zuiko lenses, because the light weight of the bodies did not provide a
greater mass that would help resist the vibration coming from the lens. Also,
talking with many men photographers, they considered that the OM bodies
were too small for their hands to hold these small bodies. They preferred
something larger and heavier. By preference, I have a winder "permanently"
attached to my favourite OM bodies, to provide a good hand-grip, and
provide a bit more mass to provide additional inertia to counteract the lens
vibration. My arms and hands are no longer heavy enough to do this on
their own. They never were like hams anyway.
The Olympus Pen series of cameras, as I understand it, have a quite
different exposure system, which does not set up a train of vibrations at
exposure time, and this helps explain why these cameras are capable of
delivering sharp images despite having an image area half that of the full-
frame 35mm system.
There are two retro-fit things I'd like to see present-day engineers design for
OM cameras and Zuiko lenses.
(1) A switch to turn off power supply and hence extend battery life.
(2) A modification to fix the aperture stop-down system fault.
I think the OM10 has such a switch (1).
Brian Swale.
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