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Lighting for 24fps


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#1 Timothy David Orme

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Posted 19 August 2006 - 10:12 PM

Most super 8 cameras are set up to shoot 18fps standard, right? So, if I'm shooting 24fps, does that mean I have to compensate my light readings/f-stops in order to get an accurate reading because 24fps lets in less light than 18fps? So, if I do compensate light, how much?

Thanks again for all your help.
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#2 Jonathan Benny

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Posted 19 August 2006 - 11:08 PM

Most super 8 cameras are set up to shoot 18fps standard, right? So, if I'm shooting 24fps, does that mean I have to compensate my light readings/f-stops in order to get an accurate reading because 24fps lets in less light than 18fps?


Open up 1/3 of a stop at 24fps vs 18fps.

You should check though if the camera makes this compensation on its own either to its internal reading and/or the lens stop when you change speeds.

AJB
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#3 Timothy David Orme

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Posted 20 August 2006 - 12:20 AM

Open up 1/3 of a stop at 24fps vs 18fps.

You should check though if the camera makes this compensation on its own either to its internal reading and/or the lens stop when you change speeds.

AJB


How do I check that information? I'm shooting with a Nizo6080 and the manual I have is in German.
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#4 Matthew W. Phillips

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Posted 20 August 2006 - 01:16 AM

I have honestly never heard of a camera that wont automatically compensate. The camera makers realize that 24fps makes a different shutter speed than 18fps, therefore, their meters should take that into regard. If you are really paranoid though, use and external incident meter.
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#5 David Leugers

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Posted 20 August 2006 - 11:52 AM

If you are using the camera's auto-exposure feature, and your camera exposes film accurately at 18fps, then just load and shoot! If you are setting the aperature manually, then yes, compensate for the higher fps rate.

David M. Leugers
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#6 Matthew Buick

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Posted 20 August 2006 - 05:36 PM

What is a Stop ?
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#7 Matthew W. Phillips

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Posted 20 August 2006 - 05:56 PM

What is a Stop ?


An F-stop is the ratio of the aperture's opening compared to the focal length of the lens. Therefore, a single stop is not a set thing.

Furthermore, each stop down halves the light intensity from the previous stop. Therefore, 2 stops has half of the light intensity as one stop.

Edited by M.W.Phillips, 20 August 2006 - 06:00 PM.

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#8 Grant Wilkinson

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Posted 21 August 2006 - 01:47 PM

matthew,

good site for picking up some manuals here:

http://www.mondofoto.com/manuals/

it seems to have one for your 6080

Grant
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#9 John Pytlak RIP

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Posted 21 August 2006 - 02:24 PM

What is a Stop ?


A "stop" is the doubling or halving of exposure.

It comes from the traditional series of "f/stops" which increment by a doubling of the area of a lens opening, thereby doubling the light coming through the lens:

widest opening -- f/0.7, f/1.0, f/1.4, f/2.0, f/2.8, f/4.0, f/5.6, f/8, f/11, f/16, f/22, f/32 -- smallest opening

Note that these increment by approximately the square root of two (1.41).

The f/stop is a simple ratio of the (focal length)/(effective iris diameter) of the lens. For example a 50mm lens with an iris diameter of 12.5mm is f/4.0. If the iris is opened up to 25 millimeters in diameter, the lens is now f/2.0 and lets in four times the light (two stops), because the area of the lens iris is now four times greater.

So a "stop" can refer to the lens opening, or any other parameter (film speed, shutter speed) that affects exposure by a factor of two.

One stop equals 0.3 log exposure unit (Log 2 = 0.30)
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