# Question On Subject Brightness Range

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• 8-Jun-2017, 04:00
IanBarber
Question On Subject Brightness Range
If a subject has a low reading of 10 EV and a high reading of 16 EV, is the SBR for this subject 7 stops (10, 11, 12, 13, 14, 15, 16) or 6 stops (11,12,13,14,15,16)
• 8-Jun-2017, 05:05
Ken Lee
Re: Question On Subject Brightness Range
A "normal" subject has a 7-stop SBR and the difference between low and high readings is 2 stops. It requires neither contraction nor expansion to look normal.

A "flat" scene has an SBR of 5 and because there are no shadows, there is no difference in readings: the difference is 0. It will require a Plus 2 expansion to look pleasing, according to the basic principles. (Of course, how we artistically render a scene is our choice.)

Because your reading indicates a difference of 4 stops, we would say that it has an SBR of 9, namely 2 more than normal. All things being equal, it requires a Minus 2 contraction to tame the high contrast.
• 8-Jun-2017, 05:34
IanBarber
Re: Question On Subject Brightness Range
Quote:

Because your reading indicates a difference of 4 stops, we would say that it has an SBR of 9, namely 2 more than normal. All things being equal, it requires a Minus 2 contraction to tame the high contrast.
Ken, could you clarify where you are calculating 9 stops sbr please
• 8-Jun-2017, 05:37
Peter De Smidt
Re: Question On Subject Brightness Range
Spot meter or incident?
• 8-Jun-2017, 05:39
IanBarber
Re: Question On Subject Brightness Range
Quote:

Originally Posted by Peter De Smidt
Spot meter or incident?

Spot meter
• 8-Jun-2017, 05:40
Peter De Smidt
Re: Question On Subject Brightness Range
I call it 6 stops. If you need detail at both extremes, I'd place 10 EV on Zone III, which would have EV 16 fall on Zone IX. With today's films, I'd use normal development, unless the scene call for non-normal tone separation.
• 8-Jun-2017, 08:17
David Schaller
Re: Question On Subject Brightness Range
I'm with Ken, and would do N-2 on that, putting the shadow in Zone III.
• 8-Jun-2017, 08:23
Leigh
Re: Question On Subject Brightness Range
Quote:

Originally Posted by Ken Lee
A "normal" subject has a 7-stop SBR and the difference between low and high readings is 2 stops.

Forgive me, Ken, but that makes no sense.

You've described SBR, but you have not defined it.

- Leigh
• 8-Jun-2017, 08:23
IanBarber
Re: Question On Subject Brightness Range
Quote:

Originally Posted by David Schaller
I'm with Ken, and would do N-2 on that, putting the shadow in Zone III.

6 stops (11,12,13,14,15,16)

Am I correct in thinking that you are removing the bottom and top reading which ends up as 4 stops.

You are then adding this to 5 to get the 9 stop SBR and applying N-2 to bring it down to the 7 stop Normal range.

Do you always use this approach whether you are using a spot meter or incident meter.
• 8-Jun-2017, 08:29
Ken Lee
Re: Question On Subject Brightness Range
Quote:

Originally Posted by IanBarber
Ken, could you clarify where you are calculating 9 stops sbr please

Sorry if I was unclear. Because you used the term SBR (which is often used by practitioners of BTZS) and you mentioned taking 2 readings (another approach from BTZS), I presumed your two readings were the standard BTZS readings, made with an incident meter in the open shadows (low reading) and direct light (high reading). My analysis was therefore based on standard BTZS nomenclature and practice.

If in fact you were simply measuring the darkest and lightest areas of the scene with a spot meter and you found a difference of 4 stops, then my BTZS analysis is not appropriate and you can ignore my reply.
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