Nikon F4 - Manual (Page 179)

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For multiple flash photography using Nikon Speedlights,
if the electric current in the sync circuit exceeds a cer­
tain level, you may not be able to take a second picture
after taking the first. Take care that the combined total of
the coefficients (numbers shown in parentheses below)
for all of the speedlights used at any one time does not
exceed 20 at 20°C/68°F (13 at 40“C/104°F).
SB-24 (1) SB-23 (4) SB-22 (6) SB-21 (4)
SB-20 (9) SB-19 (2) SB-18 (16) SB-17 (4)
SB-16 (4) SB-15 (4) SB-14 (1) SB-12 (1)
SB-11 (1)
If you are unable to take a second picture, disconnect
master speedlight from the F4, or turn each of the
speedlights off and on once.
In certain cases, due to static electricity or poorly loaded
batteries, the F4's microcomputer may turn the camera
off, even with fresh, properly installed batteries. For the
same reason, film may not advance properly. In each of
these cases, to resume operation, simply turn the power
OFF and turn ON again, or remove batteries and install
again.
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