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-   -   pulse problem (https://www.dvinfo.net/forum/canon-xh-series-hdv-camcorders/99178-pulse-problem.html)

Rocco Lobosco July 18th, 2007 05:10 AM

pulse problem
 
When i shoot with high shutter (500-1000) i've seen a strange pulse of white balance and iris, colorimetry an luminosity change randomly white a pulse effect...
the problem occour with 2 cameras (both rent from same store )and i've see it on a studio monitor.
maybe a defective series?
obviously white balance and iris is set to manual, indoor shoot and illumination with arri 1200 and 575.
Anione have this problem? ideas of this electronic strange behaviour?

thanks and excuse me for my english :)

Don Palomaki July 18th, 2007 11:10 AM

Using high shutter speed with discharge lamps can result in variations of white balance and perhaps exposure. This is because at high shutter speed, the CCD is seeing only a small portion of the lamp output over the power cycle (perhaps 15% of it, or less, at 1/1000), and that portion may have a color and brightness that is different from the average output of the lamp over the full cycle, especially near the start/end of the power pulse. The effect will be much more pronounced with standard magnetic ballasts.

Try reducing shutter speed until the undesired effect goes away. If you must use the high shutter speeds to freeze motion, try use a different type of lighting with more continuous output.

Rocco Lobosco July 18th, 2007 12:50 PM

thanks a lot for hint don :)


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