Once again I am awed by the detail of your knowledge.
Winsor
Long Beach, California, USA
On / April 17, 2008 CE, at 3:23 PM, Moose wrote:
> Chuck Norcutt wrote:
>> I agree with your reasoning regarding the mirror but I would have
>> expected a solenoid actuation in an electronic camera. And,
>> regardless
>> of how it's implemented Nikon and Pentax were both able to do it.
>>
> I don't know about Pentax, other than the screw mount ones with the
> push
> pin. The Nikon diaphragm design uses a spring in the lens to close the
> diaphragm - just the opposite of OM. When the lens is mounted, the
> aperture lever on the body pushes the diaphragm open.
>
> Thus the auto aperture mechanism in the body only needs to yield to
> the
> spring in the lens to close the diaphragm as part of the exposure. The
> "power" stroke against the spring on a Nikon body occurs in reopening
> the diaphragm after the shot, when a bit of radial vibration doesn't
> matter.
>
> The design difference, the fact that the high end mechanical bodies
> (at
> least the F2) have a mechanism to both lock up the mirror and stop
> down
> the diaphragm and the greater sheer mass of the bodies made them
> superior to the OM-1 and 2 bodies in that respect. Didn't stop me from
> switching. :-)
>
> Moose
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