Seems like 2 questions. Theoretical, and practical.
Theoretical: Like a number of cameras of that era, the Nik*n FG comes to
mind, the 2s (and PC) have a simple processor programmed with a set of
aperture/speed combinations for different light levels. Usually the
algorithm is published as a chart in the manual. Later P&S cameras and
Auto Modes on better cameras take the idea further with different
'programs' for different purposes, one emphasizing speed, another DOF, etc.
Practical: All non program OMs and the 2s and PC in other modes, simply
push the aperture closing lever on the lens as far as it will go before
opening the shutter, relying on the aperture set on the lens. In Program
Mode, they move the lever part way to set the aperture at the desired
stop. For this to work, the aperture setting on the lens has to be at
the smaller (numerically largest) aperture or the lens mechanism can
prevent the proper setting. Obviously this requires consistency in the
radial location of each aperture setting on each lens. They work with
most standard Zuikos. There is a list in the PC manual of lenses that
don't work properly in Program Mode. I've never seen a 2s manual, but
assume it also has such a list. I've compared a couple of 3rd party
lenses I like to Zuikos visually and they looked like they might work,
but you are on your own to test any you might want to use.
Moose
Fast Primes wrote:
Sorry if this is a dumb question, but how exactly, does the program
mode on the OM2S work? I can puzzle out the automatic and manual modes!
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