Handbook of High Speed Photography - IET Labs, Inc.

4.8 OPERATION OF CAMERA SHUTTERS AT HIGH SPEEDS.
At ordinary shutter-speeds, up to around one hundredth of a sec
ond, the time required to open the shutter is insignificant compared
with the time the shutter remains open (see Figure 4-9). At higher
speeds, however, the time it takes the shutter to open and close be
comes a larger and larger portion of the rated exposure time as the
size of the aperture is increased. For this reason it is advisable to
check the shutter synchronization to make sure the flash occurs when
the shutter is fully open. To do this, open the lens diaphram to its
widest aperture, remove the back of the camera to expose the rear of
the lens, aim the camera at the Strobotac reflector, and trip the shutter.
CONTACT
CAMERA SETTINGS:
1/lOS (0.1) AT f/4.5
•-TIME (SECONDS)
CAMERA
SETTINGS:
•/200S (0.005) AT «/»•»
TIME (SECONDS)
CAMERA SETTINGS:
'/200S (Q005)AT Vs
d „A , \-—to »i\
or 0*.—i—i 1 jl
0.005
I 1 TIME (SECONDS)
0.01
38
td° "ALLOWABLE FLASH DELAY"
tt CONTACT BOUNCE, TYPICALLY PRESENT
Figure 4-9. Light transmission and contact closure as a function
of time for several settings of a typical between-the-lens, "X"
synchronized shutter.