HMI flicker possible with RED?

[Doug Cragoe]

We will be shooting a RED with the new sensor "X". We will likely have HMI lights with magnetic ballasts. Do I have to keep a close eye on the generator frequency to prevent HMI flicker from showing on the image? I would if we shot film. With film I try to keep the frequency at 60.00 hertz plus or minus .15 cycle. Is this important for the RED?

Thanks for your replies.

 

[Cam Crowley]

Short answer - YES.

Basically you can adjust the shutter to compensate for any flicker but if the ballasts run at 60Htz you should be fine with a 1/30 (180deg) shutter - but definitely keep an eye on it.

I've seen flicker a few times with HMIs, but it was always fixable with an adjustment to shutter speed without compromising the image quality. If it's happening, you can see the flicker fairly quickly in the LCD/EVF/video split - there is not really a need to shoot tests. And likewise, you will not see it in the monitors if the problem does not exist or if you have fixed the shutter sync.

And shooting with an M or an MX sensor won't make any difference - if the lights and shutter are not in sync - there will be flicker.

Cam

 

[David Birdy]

The Frame rate will also effect the flicker when using 60/50Htz lighting.

The closer your frame rate is to 60 Hertz or 50 if in Europe or any county with
50 hertz power, the more flicker you will see.

If you adjust shutter and frame rate you can eliminate any flicker!

Have a great shoot!

Dave