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ASA and HVX200


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#1 Jasper Granderath

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Posted 22 August 2007 - 12:17 PM

Hey guys,

i'm starting to shoot with the HVX200 in a few days and would like to know how i should adjust my light-meter at 720pN with 25fps? I read somewhere sth about a sensitivity of 100 ASA, this can't be true, or? I've expected sth around 250 ASA. And because of the "true" progressive mode it should be ok to measure at 25fps, right?

How you would describe the Latitude of the HVX200? Are 2 stops over and under ok? Is even more possible? Would you recommend to overexpose 2/3 stop?

Thanks for helping!

Best,
Jasper
Zurich
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#2 Michael Nash

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Posted 22 August 2007 - 11:40 PM

The effective ASA will vary with the camera settings you use, namely the gamma and the black level. You'll have to do a test to find a number that works for you. But don't set your camera exposure by your light meter -- you'll end up with inconsistent exposures and clipped highlights. It's better to light -- and expose -- by a properly calibrated monitor.

Let's not confuse "latitude" with "dynamic range." I suspect you're asking how much dynamic range does the camera have; that is how much subjects can be over- or under-exposed before they lose detail. I haven't tested the HVX for actual numbers, but I would expect only about 1.5-2 stops over before things start to clip. In the shadows the camera can see quite a bit more, especially when using CineLike gamma "D" and black level set at zero. ("Latitude" describes the amount you can over- or under-expose a shot and still recover an acceptable image in post).

With video you don't want to overexpose to protect the image; if anything you want to underexpose to preserve detail. Video has very poor highlight response, but very good shadow response. Treat it opposite the way you would negative film (think of it like reversal film). Watch for clipped highlights in the monitor, and use 100% zebra stripes when in doubt. And again, use your meter for lighting if you like, but not for exposure.
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#3 John Atala

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Posted 24 August 2007 - 11:45 AM

At normal settings, its 320 asa at 3.200k preset and 250 asa at daylight.

João
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#4 Jasper Granderath

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Posted 24 August 2007 - 02:10 PM

Hi Michael, hi João!


Thank you for these informations. I will keep them in my mind while shooting. Unfortunately i will get the cam not before tomorrow in the evening and i have to start the short on sunday morning. But i've read a lot here and on other places in the www, so i feel a little prepared for the cam. the only thing i'm not shure about is the shutter speed. i will use the 720 25PN mode and don't really know which shutter speed to use for a good looking picture with panning...

hopefully i have the time to test different speeds tomorrow in the evening!

best,
Jasper
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#5 Michael Nash

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Posted 24 August 2007 - 04:24 PM

When shooting in the "film cam" mode, shutterspeeds are expressed in shutter angles. Use a 180 degree shutter angle for normal film-like motion. In "video cam" mode, shutterspeeds are expressed as fractions. Use 1/50 for normal film-like motion.
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FJS International, LLC

Technodolly

Wooden Camera

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Media Blackout - Custom Cables and AKS

Willys Widgets

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Glidecam

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The Slider

Gamma Ray Digital Inc

CineLab

Abel Cine

Rig Wheels Passport

Ritter Battery

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