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Flicker Save?


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#1 sergio cassini

sergio cassini
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Posted 12 March 2007 - 02:58 PM

i' m shooting a musicvideoclip on video in switzerland 50Hz country and would like to shoot with different frame rates.desireable fr would be 25,30 and 50 at a shutter speed of 1/50 sec.the hmi i use are not flicker free.am i flicker save with all those settings and does it dipend on the shutter speed?answers appreciated,thank you.
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#2 Michael Nash

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Posted 12 March 2007 - 05:15 PM

There are charts that show you HMI-safe frame rates for both 50Hz. and 60Hz. Looking around the web I couldn't find one to link though.

In any case, HMI-safe frame rates are easy to learn and a must for every DP to remember (or at least get a chart). Any frame rate that divides evenly into 2x the power frequency (produces a whole number) is flicker-free at any shutter angle. For 50Hz. that means any frame rate that divides evenly into 100.

For other frame rates, you only have to make sure that your shutter speed x (2x power cycle) = whole number. For example, 1/100 x 100 = 1. With a film camera you adjust the shutter angle, and with video you use the clear scan to set the right shutterspeed.
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#3 Juan Guajardo

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Posted 12 March 2007 - 06:12 PM

Use this one

HMI 50hz - Speed Chart

Luck!
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