William Sommerwerck wrote:
> The question this raises is just how the camera can provide accurate
> (ingnoring reciprocity failure) four-MINUTE exposures in OTF mode. Does
> the OTF mode use a much-higher-quality photo diode?
It´s the same SBC.
> Or is there
> something else about the design of the camera that negates the problem
> of the dark current?
No mirrors?
The OM-4 manual states an lowest EV of 0 for spot metering (with mirror) and
of EV -5 for OTF metering (exclusive mirror) at ASA100.
Translated to AS1600 it is EV4 (spot) and EV-1 (OTF),
for ASA3200, EV5 (spot) and EV0 (OTF).
Equivalent of f/1.4 and 1/8s at ASA1600, f/1.4 and 1/15s at ASA3200 in
spot mode and f/1.4 and 4s at ASA1600, f/1.4 and 2s at ASA3200 in OTF.
Regards
Richard
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