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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

How do I Remove Time-Lapse FLICKER "100%" - ??

QUOTE:

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"Shutter speed was 1/45sec to comply with our Red-One footage shot at 30fps & 1/45sec.

Yes, the strobes were camera triggered.

The strobes are modern, and each have self-contained capacitors and are plugged into normal AC current, so I doubt that too much flicker is created by them. But, that is a concern.

Thanks."

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Traditional stills shooters would be best to comment as my notions are based in the dangers of very limited knowledge. My recall is that for stills film flash photography, it was recommended for the shutter speed to be much lower, say 1/30th sec, 1/15th sec even to be assured that the full duration of the flash be included within the period the shutter was open. This was in the days of mechanical shutters. As far as motion blur was concerned the flash itself took care of it unless there were incandescant lamps or hot spots of continuous reflection in the shot in which case 1/30th sec and a steady hand was the better choice.

If you had live view going, this should have looked after any variation in trigger times as far as the mirror in the camera is concerned as the mirror would be up and not delaying the trigger.

Given that latency occurs with some digital devices, I wonder if the variation in your frames may be in part, the duration of the flash in some frames being masked by the camera closing off a small portion of the flash duration if there is variance in the response of the flash units at the units themselves or in the camera trigger system.

Long ago, there used to be two settings on film stills cameras for the flash trigger, one which compensated for the rise time of incandescent magnesium filled single-use bulbs and the other for the instaneous electronic flashes. It is there on my old Yashica rangefinder camera I had just after I left high school but gone on a Nikon FM2 which is now an old camera. I doubt if modern digital stills cameras retain these two trigger settings as a legacy thing to check for. The slower shutter speed may remain a valid practice as a hedge against slight delays in the flashes going off and partially missing the entire period of the electronic shutter being "open".

My last thought is in the strobes themselves. I assume they are the "U" shaped xenon flash tubes in parabolic reflectors. If there is variation in the path the flash takes within the thickness of the tube, that might cause a flicker through the focussed beam shifting offcentre one way or another between frames. If this is going on, I would expect that there would be stronger zones of brightness in some frames and stronger zones of brightness in different areas in other frames. If backgrounds are dark or distant out of the flash zone, then the main illuminated subject would flicker.

To defeat that tendency if indeed it even exists, I would prefer to bounce the strobes off a reflective flat panel, not umbrella or diffuse the flash with a large diffuser say two feet forward of the strobe. By this means I would hope to reduce the effect of an off-axis shift of the main flash beam due to movement of the hotspot within the xenon tube from shot to shot.

I hope this is not a goosechase for you.
 
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