Hasselblad 500C/M Instruction Manual page 10

Fig 12
Shutter speeds: 1 to 1/500 s and B.
At the B setting, the shut-
ter remains open as long as
the shutter release is de-
pressed.
Always use a cable release
for long exposures.
NOTE Some films may display a loss of
speed in very long exposures (reci-
procity failure). Any exposure com-
pensation necessary here is usually
specified by the film manufacturer.
Warning signal
There is a red marking on the shutter
speed scale opposite the 1, 1/2, and 1/4
s. This is to warn against possible expo-
sure errors. The auxiliary shutter re-
mains open as long as pressure is main-
tained on the shutter release. If the pres-
sure is relaxed too soon, the auxiliary
shutter will terminate the exposure pre-
maturely. So make a habit of main-
taining pressure on the shutter release
until the leaf shutter has opened and
closed fully.
Exposure values (Fig. 13)
The aperture and shutter speed combination
set opposite the central index (5) determines
the exposure. Every combination of shutter
speed/aperture has an equivalent exposure
value (8).