Need some advice gh1 stage lighting...

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dotdotdot

Member
hi there, this is my first post on this site so if i have done it in the wrong place, or this has been answered before i i apologise (i did find a simular post here but got a little lost in the technical aspect http://www.dvxuser.com/V6/showthrea...-noted-under-LED-stage-lighting-example-video.) .

i am needing some help with shooting some performances of my better half on stage. I am using a gh13 with the kit lens at the moment just to trial, and running into trouble with lighting. i am in the uk so am shooting at 1080p 25p at shutter speed 50, and am getting flicker from some of the light. The white lights are fine but the blue seem to screw with me. video is here http://vimeo.com/22054223
i thought that shooting at 25p would enable me not to have no flicker but this seems only to be working with white lights, any ideas on what avenues i should take before i try again? i guess i'll go next time and play with the fps and the shutter speed trail and error wise, but any advice would be most appreciated.

thanks
 
I left a comment on your vid. To summarize quickly here, different lenses might help and.....those flickering lights are only noticible to those who know about these issues. 95% of your audience won't notice it or will think it's a artistic choice. Flickering lights in a club or on stage doesn't usually seem out of place. Maybe have the lights pointed away a bit so they're not together and/or add some other light sources that flash or blink to add to the effect.

Also, people are looking at your wife so make sure she's the focus and make sure she's most noticible on stage....and she is. :thumbsup:
 
thanks for the advice mate, i left u a msg on vimeo, will be getting a low light lens working soon so i will hopefully see the difference, will be filming always with no control of lighting etc... so its gonna be fun on the fly!

thanks!
 
Try a shutter speed of 1/40 and see if that fixes the flicker, you should see it already on the LCD screen. I've seen some LED fixtures that seem to run at 80 Hz for some reason. You can also try going up to 1/60.
 
Martti Ekstrand said:
Try a shutter speed of 1/40 and see if that fixes the flicker, you should see it already on the LCD screen. I've seen some LED fixtures that seem to run at 80 Hz for some reason. You can also try going up to 1/60.
Click to expand...

LED lights in night club venues seem to be on the rise, and some of them have pulse rates that are not safe for cameas at any shutterspeed... (well reasonable sutter speed....).

From the look of the blue lights in the sample, I'd say it looks like the same sort of thing another thread showed, in the Lighting section (as mentioned by the OP...), and due to the LED lights being run at a rate that doesn't lend itself to easy shutter speed correction.
 
dotdotdot said:
hi there, this is my first post on this site so if i have done it in the wrong place, or this has been answered before i i apologise (i did find a simular post here but got a little lost in the technical aspect http://www.dvxuser.com/V6/showthrea...-noted-under-LED-stage-lighting-example-video.) .

i am needing some help with shooting some performances of my better half on stage. I am using a gh13 with the kit lens at the moment just to trial, and running into trouble with lighting. i am in the uk so am shooting at 1080p 25p at shutter speed 50, and am getting flicker from some of the light. The white lights are fine but the blue seem to screw with me. video is here http://vimeo.com/22054223
i thought that shooting at 25p would enable me not to have no flicker but this seems only to be working with white lights, any ideas on what avenues i should take before i try again? i guess i'll go next time and play with the fps and the shutter speed trail and error wise, but any advice would be most appreciated.

thanks
Click to expand...

Briefly, yes you can 'correct' a bit for flicker by adjusting the shutter speed, if the flicker rate is related to the shutter speed. If in the case of what you seem to have, and the thread in the lighting section you reference, the 'flicker' rate is not really related to shutter speeds your camera has... then you may be stuck with the artifact.

In PAL countries the Power line frequency is 50 Hz, and so, setting your shutter speed to 1/50 will mitigate the flicker... in NTSC countries for the most part, it's 60 Hz therefore 1/60 shutter speed is recommended.

The problem with the LEDS in this sort of situation, is that the timing base is not necessarily related to the power frequency... in other words it could be 41 Hz, or 410 Hz... who knows. There's no standard... and so, it is very difficult to find a correcting/mitigating shutter speed with such variations.

LED lights that are designed for film applications, are designed such that any frequency used is one that will not cause problems for the camera, or at least the frequency specified and shutter speeds recommended...

One idea that does occur to me. You could perhaps do some post processing on the video. This is just an idea, but using After Effects create a track that has all but the blue masked off, you can 'key' on the blue. Create a track that has the blue area keyed, and then replace it with a frame averaged version to 'average' out the flicker.

The problem is that the performer's and the rings reach into the the 'blue', so you need the 'key' to basically allow her hand props to be represented correctly...

Don't know if that would 'work', but it's something I'd try...
 
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