# Zone System / Waveform monitor relationship

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### #1 EDDUS RAY

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Posted 25 August 2012 - 07:22 PM

Does anyone have any information regarding the application of the Zone System to the waveform monitor? Do certain Zones fall over IRE brackets? I.E. Zone V @ say 50 IRE'S...?

Edited by Judson Lee, 25 August 2012 - 07:23 PM.

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### #2 Phillip Jackson

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Posted 27 August 2012 - 11:01 AM

From my understanding no, that's not the case. IRE is a percentage based value for the video signal being broadcast and since each camera has a different dynamic range the values shown by the IRE will relate to each dynamic range differently. You'd have to do tests with a grey scale (with your shooting camera) to really be able to know how to read the IRE values in stops. This isn't even considering the fact that IRE are logarithmic and not linear so it won't 6 IRE = 1 stop throughout the waveform.
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### #3 EDDUS RAY

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Posted 11 September 2012 - 07:09 PM

From my understanding no, that's not the case. IRE is a percentage based value for the video signal being broadcast and since each camera has a different dynamic range the values shown by the IRE will relate to each dynamic range differently. You'd have to do tests with a grey scale (with your shooting camera) to really be able to know how to read the IRE values in stops. This isn't even considering the fact that IRE are logarithmic and not linear so it won't 6 IRE = 1 stop throughout the waveform.

Thanks man, that make sense.
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### #4 Bruce Southerland

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Posted 23 September 2012 - 10:13 AM

There's an article in the American Cinematographer video manual 3rd Ed. titled "How to use the zone system to predict
Video image contrast", which discusses the relationship of IRE units and the zone system, if you can get you hands on
one. I bought my copy on half.com.
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### #5 David Mullen ASC

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Posted 23 September 2012 - 10:58 AM

The other issue is whether you are applying the Zone System concept to a Rec.709 signal or a flatter Log gamma, which would contain more or less the total stops of DR captured.
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