Does anyone know how the camera's (MZ-S and Super Program) on-board metering
works when there is no communication between the camera and the lens?
Specifically, I am using the auto bellows and a 100mm macro lens and am
consistently getting underexposed negatives. I generally find +2 to +3
stops of compensation is required to get correct exposure. All of the
"macro" books speak of the difficulties with metering subjects above 1x but
then say that "if TTL is used this overcomes the necessity of determining
the magnification ratio and exposure compensation."
My understanding of TTL was that it is "Through the Lens Metering" that can
control not only a Flash but also meters throughout the exposure of a
negative to ensure correct exposure. Since the bellows does not communicate
with the lens, the camera does not "know" the F-stop. Hence, I stop down
the lens with the cable release, meter (based on the reading in the
viewfinder), adjust my shutter speed and, if I believe the camera's reading
get an underexposed picture every time.
All I can figure is that the camera, if it does not have communication with
a lens, assumes some f-stop such as a wide open f2, and this negatively
impacts the correct exposure reading. Alternatively, perhaps when the
camera is in communication with a lens, TTL works throughout the exposure,
and when you switch to manual, you only get the instantaneous reading prior
to releasing the shutter and is thus less accurate.
Any help is appreciated.
Jason
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