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Movie Light Meter App


Don Cole

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I've used a Sekonic light meter a few years ago in college when I had access to rent it and a 16mm Bolex. I just bought my very own Bolex and need a light meter, but don't want to have to spend another $100 or so to buy a Sekonic on ebay. I was hoping there would be an light meter app I could use instead, at least for now, but they all seem to be only for still photography. Does anyone know a good movie film light meter app I can use with my Bolex?

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It's easy to use a still photography light meter for motion pictures.  One just needs to know the ISO setting and the actual shutter speed that you will be employing.  I believe the Bolex shutter speed at 24fps is 1/65th sec.  But one must also increase exposure to compensate for the viewing prism/mirror and that means one should set the shutter to 1/80th sec on your light meter.

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  • 1 month later...
On 10/9/2019 at 2:23 PM, Bruce Greene said:

It's easy to use a still photography light meter for motion pictures.  One just needs to know the ISO setting and the actual shutter speed that you will be employing.  I believe the Bolex shutter speed at 24fps is 1/65th sec.  But one must also increase exposure to compensate for the viewing prism/mirror and that means one should set the shutter to 1/80th sec on your light meter.

Okay, thank you! But how does that change if I change the frame rate like to 32 or 64 fps? I can't seem to find anything about that online.

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Well the viewing mirror is a fixed 1/3 stop adjustment approximately.  32 fps is about 1/3 stop faster than 24fps.  So, add 2/3 stop less exposure for shooting at 32fps, which is about 1/100th sec shutter speed equivalent. 64fps is about 1 + 1/3 stop less light, plus the viewing mirror loss so about 1 + 2/3 stop light loss vs 1/65th sec when shooting 64fps.  Which comes out to about 1/200th sec exposure on your light meter.

So, you see, the jr. high school math does come in handy in photography!

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