Hi Roger and other fellow Zuiks.
>
> Date: Tue, 25 Dec 2001 12:43:02 -0500
> From: "roger skully" <robinsnes@xxxxxxxx>
> Subject: Re: [OM] (Fwd) DOF button.
>
> Why disable it or hinder your focusing abilities? I cannot think of any
> reason (not that there may not be one) for doing this.
> Roger Skully
> robinsnestphotography.com
Well, the logic behind it goes like this, as I understand it.
The 35mm system has a small negative. So for best results a bit more care
is needed to eliminate anything that might contribute to unsharpness.
There are at least three 'in camera' sources of vibration that actually do
result
i lowered contrast and definition (see Gary Reese's lens tests - he
comments on this frequently). They are:-
Mirror operation
Diaphragm operation
Focal-plane shutter operation.
Mirror vibration is dealt with by raising the mirror (OM1) and pre-fire in self-
timer operation (OM4), and the delay that allows the vibration to die away.
Diaphragm vibration is dealt with in the OM4 by pre-fire, and not at all in any
other OM body. Hence the wish to close down the OM1 diaphragm once the
picture is composed and when the mirror is up. Then all that is necessary is
for the subject to quit moving.
Shutter vibration is dealt with by attaching as much mass as possible to the
camera. Clamp it to a mountain if possible. Otherwise, use a heavy tripod,
something heavy at the tripod head or attached to the camera, push down
on it to anchor it to mother earth, and maybe hand-hold it as well to dampen
the residual vibrations.
And as I said previously, the OM1 has it all over the OM4 in this regard since
it is possible to get everything all set, and as soon as the wind stops - or
whatever - trip the shutter. There is no way to do the equivalent with an OM4.
With the OM4 you have to let the self-timer do its thing which takes 10+
seconds. OK for a subject that doesn't move, such as a mountain, but for
flowers, insects etc in macro mode etc - no way.
Does that cover it?
I agree that for wedding photography, things may be a little different. But the
principles remain the same, in my view. And you will be very concerned with
fine details of lighting, group composition, interactions and facial
expressions
that don't really come into it to the same degree with flowers. Well, lighting
and composition do. But you have to use your imagination to see a smile.
Cheers, Brian
...................................................
Zuikoholics, enablers, one and all.
Feeding fantasies, emptying pockets!
---------------------------------------------------
Brian Swale, 140 Panorama Road,
Christchurch 8008, N.Z.
Tel +64 3 326 7447
http://homepages.caverock.net.nz/~bj/photography/
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