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Colored LED light flicker

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Casey Petersen
Colored LED light flicker
on Sep 18, 2012 at 7:39:39 pm

When I film weddings and receptions, usually during the dance, the DJ has these really bright colored LED lights as part of the light show. It looks good to the naked eye, but it looks awful on DSLR video (Canon 60D specifically).

Not only are the lights bright and intense shades of reds greens and blues, but there is something in the frequency of these lights that cause a flicker at every shutter speed, but is least noticeable at the shutter speed of 30, but it is still certainly there.

I'm wondering what other people have done to help alleviate these problems...both the color intensity and the flicker issues. Any advice would be welcome.

Thanks!
Casey


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Phil Balsdon
Re: Colored LED light flicker
on Sep 19, 2012 at 3:34:23 am

This is probably an issue to do with electric current frequency powering the LEDs. Unlike good true video cameras HDSLRs do not have a variable clear scan shutter adjustment (most commonly used for syncing CRT computer screens or fluorescent lights in foreign countries). Clear scan allows you to set precise shutter speeds of say 1/59.6 and sync your frame rate to the current frequency or scan rate of a computer screen.

You are stuck with 1/25, 1/50, 1/60 etc. typical of still photographic cameras.

If this is the cause there's virtually no fix in the camera.

Cinematographer, Steadicam Operator, Final Cut Pro Post Production.
http://philming.com.au
http://www.steadi-onfilms.com.au/


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Peter Burger
Re: Colored LED light flicker
on Sep 19, 2012 at 8:58:41 am

[Phil Balsdon] "This is probably an issue to do with electric current frequency powering the LEDs. (...) If this is the cause there's virtually no fix in the camera."

Yes, exactly. Even LEDs that won't show any flicker when at full power will flicker while dimming.

------------------------------------------
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Phil Balsdon
Re: Colored LED light flicker
on Sep 19, 2012 at 11:45:30 am

This is a great video shot by my friend Rod Turnbull using the high speed function on a Sony NEX FS-700. Take a close look at the head lights of the red car. The LED trim lights around the bottom edges flicker very noticeably in slow mo shots. Not a problem in the static hero shots at the end though when using regular frame rate.







Apparently this was also a problem for TV coverage in the Le Mans 24 hour race where some cars now use full LED headlights.

Cinematographer, Steadicam Operator, Final Cut Pro Post Production.
http://philming.com.au
http://www.steadi-onfilms.com.au/


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Casey Petersen
Re: Colored LED light flicker
on Sep 19, 2012 at 2:49:01 pm

I see...is there anything that can be done in post to minimize it?

Thanks!
Casey



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Brent Dunn
Re: Colored LED light flicker
on Sep 19, 2012 at 3:50:35 pm

There is a fluorescent setting in the camera white balance settings that may help. I had a recent issue with fluorescent lighting and it helps. Not sure what to do in post.

Brent Dunn
Owner / Director / Editor
DunnRight Films
DunnRight Video.com
Video Marketing Toolbox.net

Sony EX-1,
Canon 5D Mark II
Canon 7D
Mac Pro Tower, Quad Core,
with Final Cut Studio

HP i7 Quad laptop
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Phil Balsdon
Re: Colored LED light flicker
on Sep 19, 2012 at 9:52:58 pm

Fluorescent setting is only for color balance and won't fix the flicker.

Cinematographer, Steadicam Operator, Final Cut Pro Post Production.
http://philming.com.au
http://www.steadi-onfilms.com.au/


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Grant Strac
Re: Colored LED light flicker
on May 5, 2014 at 5:54:13 pm

Did you ever figure this out? I shot something that I couldn't see how bad the banding was. I need to fix it so any post suggestions will help.


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Casey Petersen
Re: Colored LED light flicker
on May 8, 2014 at 3:01:23 pm

Nope, never did



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Chris Wright
Re: Colored LED light flicker
on Sep 19, 2012 at 11:48:32 pm

is the whole screen flickering or just small points of light?

what do you mean by color intensity? too much saturation? or glowing extremes from off to light burst?

this might work
http://forums.creativecow.net/readpost/280/9578


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