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Light Meter question.


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#1 Pawel Saladziak

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Posted 05 April 2007 - 11:24 AM

Hi. I'm considering buying a light meter, I want to use it for shooting 96 fps 25 fps and in future 500 fps on 16mm and super16mm.

For two first speeds I have already some candidates (by the way does anyone here use these?) :

1. Minolta Autometer IV F
2. Sekonic (358 or 558 cine)
3. Spectra Cine meter (the digital one)

But for the slomo shooting (500 fps) I do not know what kind of metering tool should I use. Latest Sekonic meters have only 360 fps.

Best regards
Pawel
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#2 Charles MacDonald

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Posted 05 April 2007 - 07:59 PM

But for the slomo shooting (500 fps) I do not know what kind of metering tool should I use. Latest Sekonic meters have only 360 fps.

to getanywhere near that high a frame rate would take special High speed camera, perhaps with an unconventional shutter. (like a prisim editor only backwards.)

The camera would have an equivelent shutter speed, and you would have to calulate the exposure.. 500 FPS is likly ot have a shutter speed around 1/1000 of a second, and you would read off the scale for a still camera. BUT you would have to read the manual of the High-speed camera to find out what the effective speed is, and also what light loss their is if it does have prisim optics.

Same problem if you have a camera with a variable shutter BTW.
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#3 Fran Kuhn

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Posted 05 April 2007 - 07:59 PM

But for the slomo shooting (500 fps) I do not know what kind of metering tool should I use.

Pawel,

I've had good luck with the Seconics and the Spectra. I find the Seconic, with it's variable shutter angle settings and built-in spot meter a little more convenient.

If your meter won't go to 500 fps, just use a multiple of 500 to calculate your exposure. For instance, if your meter goes to 125 fps, take a reading at this setting and simply open up two stops to get the equivalent exposure at 500 fps. At 500 fps, the film will be exposed only 1/4 as long as it would at 125 fps so you need to give it four times the amount of light (opening the aperture one stop is equal to twice as much light; two stops equals four times the amount of light.)

-Fran
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#4 Fran Kuhn

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Posted 05 April 2007 - 08:30 PM

to getanywhere near that high a frame rate would take special High speed camera, perhaps with an unconventional shutter. (like a prisim editor only backwards.)

Hi Charles,

The first film shoot I ever did was with one of those Photo-Sonics Actionmaster 500s. Great name--sounds like something you'd buy from a Ron Popiel infomercial. Here?s a link that has the camera?s specs: http://www.photosoni...nmaster_cam.htm

There are two models, standard and Super 16. The Super goes to 360 fps; the standard takes double-perf film and will go to 500fps; it?s got a shutter that can be set between 7.5 degrees and 160 degrees. There's a chart that lists exposure times at various shutter angles. Your calculation was pretty close: At 500fps it?s 1/1125th second with the shutter set at 160 degrees.

The film looked great at 500fps, but the thing sounds like a spooled-up turbine at that speed. Mag jams are pretty spectacular, too.

-Fran
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#5 Pawel Saladziak

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Posted 06 April 2007 - 09:26 AM

well, due to budget limitations I decided to buy two lightmeters (that sound's funny ha...) but these are used ones:

1. Spectra S-501 meter
2. Gossen Luna Pro F meter

How do you think, is this a good choice? I both of them give same readings will this mean that they are still properly calibrated?

The 500fps shooting will wait a bit. And I will try 96fps shooting first.

best regards
Pawel
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#6 Rupe Whiteman

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Posted 06 April 2007 - 11:35 AM

The Asc Manual and Samuelsons manual usually list the relative exposure stops for different frame rates... I've shot 16mm photosonics at 25Ofps - was given the stop at 24 by the dop then just looked up the table in the manual. Job done.
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