Hmmm,
Now I don't just seem to get how the estimated 2nd curtain with the OTF
metering can't be faster than 1/60 sec and thus exceed the synch speed
if the camera doesn't know a flash is attached. Say the flash is in
auto and the sensor sees a darker background and thus would overexpose
relative to the OTF metering---as the flash duration is very small
relative
to the exposure time, it would seem the 2nd curtain could be caused to
limit the exposure to something under 1/60th and thus lead to uneven
exposure of the frame.
Perhaps I just need to re-think about it after coffee in the AM.
Perhaps I'll also regret this post and slap my forehead.
A. Still Confused Mike
(in review, OM2 in TTL auto, T32 in normal auto)
>
> Correct for TTL mode where the camera is in control of the
> flash exposure. For auto or manual flash where the only
> control available to the camera is the shutter speed you
> wouldn't get uneven exposure nor underexposure but you could
> get overexposure.
>
Well assuming a fully manual calculation of flash exposure or the flash
set
to "normal auto" with say an aperture of f8. As long as the ambient
light
would lead to an exposure of > 1/60 (say (1/8), first curtain opens
fully,
flash fires, OTF metering sets the second curtain on it's way, the
resultant
exposure is probably about 1/60 f8. If the flash is giving less light
than
expected then the OTF metering just holds back the second curtain until
the
ambient makes up the difference. You may get overexposure if your
manual
flash calculation isn't correct or if the "normal auto" mode gives more
light than it should.
...Wayne
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