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Can someone please double check my math?


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#1 Jay Young

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Posted 17 February 2017 - 06:15 PM

Shooting 800iso + 45-degree shutter = 2 stops loss

 

Set light meter for 24fps @ 200iso = this is what I set on the lens

 

Working stop of T8 should reflect that on the meter @200 iso correct? 

 

OR, I can set the meter at 800, and subtract 2 stops. 

 

16 on the meter = 8 on my camera.  

 

 

Secondly, I should be able to key light with a 650w Tungsten Fresnel at full spot from 10' which should give about 500fc.  

Then, I can use a 5K at 20' on flood to provide about 200fc, or two stops down for fill.  

 

Does that sound about right? 


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#2 David Mullen ASC

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Posted 17 February 2017 - 06:41 PM

Yes, f/16 at 800 ASA is the same as f/8 at 200 ASA.

 

Not sure you're going to get an f/8 at 200 ASA with a tweenie at full spot from 10' away...


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#3 Igor Trajkovski

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Posted 17 February 2017 - 08:04 PM

According to ARRI Interactive Photometric Calculator:

ARRi 650 Fresnel, Spot, @10 feet, 800ISO, 45degree 24fps.jpg


...


 


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#4 David Mullen ASC

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Posted 17 February 2017 - 08:26 PM

OK... seems to work on paper.  At least there will be a 5K on hand if you want to key with the 5K and fill with the 650w.


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#5 Jay Young

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Posted 17 February 2017 - 08:40 PM

OK... seems to work on paper.  At least there will be a 5K on hand if you want to key with the 5K and fill with the 650w.



I laughed muchly at this. Good show!

I thought about keying with the 5k, but I would need a much less sensitive medium... I'm going to test in a day or twould and see how much I can get out of a tweeny.
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