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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 :)

HMI flicker

Brian D. Goff

Brian D. Goff

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Hi

Just getting ready for a classical RED vs. Film debate:)

So what I need to know:

Will the RED camera more likely encounter HMI flicker while shooting 24/25p compared to a Film camera?

Thanks
 
On build 16 and earlier, I had no HMI flicker at 23.98 and 1/48th shutter. After build 16, mag ballasts and discharge lighting had very subtle rolling pulse at the same. Went away at 1/60th shutter. Right now, MX seems to shoot just fine at 24p and 180 degrees (23.98 1/48th). I am shooting in denmark at the moment, and had subtle flickering issues with LED lighting until I went to 1/50th shutter, so go figure.

Cheers,

Nick
 
Nick Gardner said:
On build 16 and earlier, I had no HMI flicker at 23.98 and 1/48th shutter. After build 16, mag ballasts and discharge lighting had very subtle rolling pulse at the same. Went away at 1/60th shutter. Right now, MX seems to shoot just fine at 24p and 180 degrees (23.98 1/48th). I am shooting in denmark at the moment, and had subtle flickering issues with LED lighting until I went to 1/50th shutter, so go figure.

Cheers,

Nick
Click to expand...

Hi Nick

So if I want to go 24p, the project frame rate is set to 23.98?

Thanks
 
Nick Gardner said:
On build 16 and earlier, I had no HMI flicker at 23.98 and 1/48th shutter. After build 16, mag ballasts and discharge lighting had very subtle rolling pulse at the same. Went away at 1/60th shutter. Right now, MX seems to shoot just fine at 24p and 180 degrees (23.98 1/48th). I am shooting in denmark at the moment, and had subtle flickering issues with LED lighting until I went to 1/50th shutter, so go figure.

Cheers,

Nick
Click to expand...

That's because Denmark's power and lighting is at 50Hz rather than 60Hz.
 
@ Lee - Yeah, that's why I went to 1/50th, I was expressing surprise at the fact that my LEDs were flickering not that it went away at 1/50th of a second.

@ Tony - I was in Copenhagen for a week shooting about 70 pieces of art at the David Collection. The most civilized shoot I have ever done. We got up at a reasonable hour, walked 5 minutes to the museum, shot fabulous treasures on a turntable for 4 hours, had a fantastic lunch, came back and shot for another 3 hrs. Fantastic dinner. Repeat ;-)

Nick
 
Yeah, I find it weird that LEDs often flicker, too - I'd of thought they'd be rock solid.

I shot a music festival down here in Brighton recently, and maybe 70% of the venues (it was in various clubs around the town, rather than out in a field - kind of like SXSW) that had LED parcans would flicker at me, requiring pretty weird shutter angles to get rid of them (and in one smaller venue they proved impossible to completely cure - perhaps they had a bunch of different heads flickering at different rates).

Bizzare, and - I would imagine - a bit of a worry for those that do a lot of live music/event filming...
 
A slight deviation of the topic but I thought it may be of interest. We have been using the new Arri D-HS (digital high speed) ballast for our HMI lights in studio. I believe they cycle 1000 times per second opposed to the 50 or standard Flicker Free Modes that are available.

Here is a link to a low res test with our findings: http://suginostudios.wiredrive.com/l/p/?presentation=17cd811870d10d4998adcf2cf6ff571e

Hard to believe, but the slate actually says Flicker Test and not what your thinking!!!
 
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