Digital Cinematography, 2nd Edition

466 Chapter 11

time durations. While the frequencies are usu-

ally higher than cinema frame rates, icker can

manifest itself at some intensity or color settings

and disappear at others depending on how the

timing and duration of particular pulses interact

with the shutter speed and shutter angle. Fixtures

manufactured specically for motion picture use

generally work at very high frequencies which

helps to avoid icker for normal shooting, but

for high speed photography cinematographers

should either test or use constant current LED

xtures. If LED lights in your shot don’t seem

to obey the rules of known 50 cycle or 60 cycle

shutter ...