At 10:37 18/10/99 EDT, Pauls0627@xxxxxxx wrote:
>I always thought that the early OM-2 models were centerweighted when
>measuring off the curtain, and full frame averaging when metering off the
>film. So as shutter speeds got longer the amount of center weighting
>gradually diminished. With the change to the new curtain pattern I thought
>the center weighting was somehow built in to the way the photo cells read
teh
>light, so there is the same amount of center weighting at all shutter speeds.
>
It occurs to me that there is another aspect to this - in manual mode don't
the OM-2 and 2n use a different meter altogether, in the prism like the
OM-1? So this business of shutter-curtain patterns presumably only matters
in auto mode.
Photodiodes, like most sensors, have a sensitivity which varies according
to the angle of incidence of the light, so if the metering diode has a
fairly narrow acceptance angle then the metering will be centre-weighted,
to some extent regardless of the pattern on the curtain.
Richard
Richard Ross
Hemel Hempstead, England
richard@xxxxxxxxxxxxxxx
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