GH2 24p and 50Hz lights - any examples of problems encountered?

Lucas Adamson

Lucas Adamson

Well-known member
So, I have a GH2 and I live in the UK, a country with a 50Hz electrical system, and hence a 25p standard (PAL) for shooting video and film.

We are taught at film school to NEVER shoot at 24p in the UK. I know old CRT monitors could be problematic, with a strobing bar moving up the screen on all shots.

I am told that this can also cause real problems with some lights, but having NEVER shot 24p before, I'm not sure whether the warnings not to shoot 24p here for serious work are important or not.

Any video examples of 24p work that's gone wrong due to 50 Hz (PAL country) lights please?
 
I recently shot a fast dance routine using 24p Cinema mode on the GH2 and the lighting was all PAR 56/64 tungsten. Didn't notice any problems with strobing or flicker. I've also used battery-powered LED lights while shooting in this mode and again, no problems.
 
Well, LED and any other battery lights are actually all fine, because they are DC, not AC, hence constant, not flickering like all unregulated AC lights.

Do you mean 5600K and 6400K tungsten, or what?

Yes, some AC lights are fine. If anybody can tell me which are the worst for 24p flicker, I'd love to know? It would be great to discover this problem is blown out of proportion, for example...
 

I was shooting at high shutter speeds which I have read is the cause of the banding. Lowering shutters speeds below 1/125 may fix it. Starts at :39.
 
Typically, shooting with a shutter speed that's a multiple of the AC system means that there'll be no flicker at all, even in 24p mode. It sounds odd, and I can't quite get my own head around how it works, but it does, and it works well.

Japan uses 50hz and 60hz electricity depending on the region, so they might have developed some way of making it dependent on the shutter speed rather than the framerate.

In any case, just shoot with a shutter speed of 50 and you'll be fine.
 
One of my students went to Cambodia this summer and had issues with his 7D. I am guessing it was from a shutter and lighting issue. 50 seconds in you can see what is happening. He said he tried a few shutter speeds and couldn't get rid of it.

 
I don't know what the colour temperature of the PAR lights was, but would this have any effect? Regarding the Cambodia flicker 50 seconds in: could it be a ceiling fan getting in the way of the light? Just a guess, but who knows?
 
AFAIK, as long as your shutter speed is 1/50 then you should be flicker free at 24p in the UK. Best to shoot some tests..
 
David Parsons said:
I don't know what the colour temperature of the PAR lights was, but would this have any effect? Regarding the Cambodia flicker 50 seconds in: could it be a ceiling fan getting in the way of the light? Just a guess, but who knows?
Click to expand...
My guess, too. Or other shutter than 1/50th or 1/100th.
 
You can get bad strobing from lights at any frame rate with older lights. It is the shutter speed, not the frame rate in my experience that is the main issue. But there's lots of different kinds of lights....
 
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