Page 1 of 7 123 ... LastLast
Results 1 to 10 of 66

Thread: Question On Subject Brightness Range

  1. #1

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    306

    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)

  2. #2

    Join Date
    Sep 2003
    Location
    Massachusetts USA
    Posts
    7,797

    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.

  3. #3

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    306

    Re: Question On Subject Brightness Range

    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

  4. #4
    Peter De Smidt's Avatar
    Join Date
    Jan 2001
    Location
    Fond du Lac, WI, USA
    Posts
    5,325

    Re: Question On Subject Brightness Range

    Spot meter or incident?
    "Why can't we all just get along?" President Dale, Mars Attacks

  5. #5

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    306

    Re: Question On Subject Brightness Range

    Quote Originally Posted by Peter De Smidt View Post
    Spot meter or incident?
    Spot meter

  6. #6
    Peter De Smidt's Avatar
    Join Date
    Jan 2001
    Location
    Fond du Lac, WI, USA
    Posts
    5,325

    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.
    "Why can't we all just get along?" President Dale, Mars Attacks

  7. #7
    David Schaller
    Join Date
    Mar 2002
    Location
    Williamstown, MA
    Posts
    458

    Re: Question On Subject Brightness Range

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

  8. #8
    8x10, 5x7, 4x5, et al Leigh's Avatar
    Join Date
    Dec 2010
    Location
    Maryland, USA
    Posts
    4,982

    Re: Question On Subject Brightness Range

    Quote Originally Posted by Ken Lee View Post
    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.

    Could you please define it?

    - Leigh
    If you believe you can, or you believe you can't... you're right.

  9. #9

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    306

    Re: Question On Subject Brightness Range

    Quote Originally Posted by David Schaller View Post
    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.

  10. #10

    Join Date
    Sep 2003
    Location
    Massachusetts USA
    Posts
    7,797

    Re: Question On Subject Brightness Range

    Quote Originally Posted by IanBarber View Post
    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.
    Last edited by Ken Lee; 8-Jun-2017 at 16:24.

Similar Threads

  1. Question about a specific subject and composition
    By DaveF in forum Style & Technique
    Replies: 25
    Last Post: 4-Oct-2017, 06:40
  2. Ektar 100, Porta 160, Porta 400 Subject Brightness Range
    By Mark Stahlke in forum Darkroom: Film, Processing & Printing
    Replies: 6
    Last Post: 22-May-2013, 09:06
  3. 18 stop Subject Brightness Range on Tmax400
    By Steve Gledhill in forum Digital Processing
    Replies: 43
    Last Post: 23-Nov-2009, 18:08
  4. Very High Brightness Range
    By Ian_5357 in forum Darkroom: Film, Processing & Printing
    Replies: 19
    Last Post: 13-Apr-2005, 08:00
  5. Question on brightness of GG
    By Pascal Quint in forum Cameras & Camera Accessories
    Replies: 4
    Last Post: 29-Jan-2002, 06:39

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •