Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,685   Posts: 1,548,581   Online: 1150
      
Page 7 of 8 FirstFirst 12345678 LastLast
Results 61 to 70 of 80
  1. #61

    Join Date
    Jun 2004
    Location
    Portland, OR
    Shooter
    4x5 Format
    Posts
    3,268
    Quote Originally Posted by sanking
    Kirk, Yeah, that would have worked fine for me. But if he had used SIR what would we be obsessing about now?
    Sandy
    Probably about whether SBR would have made more sense - or if 5 stops was a good choice.

    I have to say, I'm not really obsessing about it as I don't have much time invested in it. Other than the sometimes unobtainable quest for the perfect abbreviation, it's fine with me.

    Do you have any suggestions on one, just for fun?

  2. #62
    Ole
    Ole is offline
    Ole's Avatar
    Join Date
    Sep 2002
    Location
    Bergen, Norway
    Shooter
    Large Format
    Posts
    9,281
    Blog Entries
    1
    Images
    31
    Quote Originally Posted by Jorge
    huh......good try but you rnumbers are not realistic, go out on the field and try it and get back to me...
    Jorge, those numbers ARE from field experience. The high range is the "Bridge" photo which I eventually had to lith print to reproduce the full range of highlight tones, the low range is my little waterfall on a rainy day.
    -- Ole Tjugen, Luddite Elitist
    Norway

  3. #63

    Join Date
    Dec 2004
    Location
    Milwaukee, Wi
    Shooter
    35mm
    Posts
    3,242
    Just a crazy thought. If the topic is for example BTZS techniques then those that post information should be cognizant with BTZS terminology and understand its usage. If the posting is about sensitometry then the appropriate terms from that field of discipline should be used. If someone is not familar with the terms of either methodology then they may be well advised to ask what a particular term means.

    If concepts that are not understood by anyone except the writer are used I believe that either a lot of confusion may result or no real communication will transpire. The confusion may well be replaced by ACRIMONY.

    I, for one, welcome the opportunity to contribute as well as to learn.

  4. #64

    Join Date
    Dec 2002
    Shooter
    Large Format
    Posts
    6,242
    [QUOTE=Ole]
    Quote Originally Posted by Jorge
    ...
    Spot meter readings can be converted to SBRs by the following formula:

    SBR=(7*(D-N))/D

    where:
    D= spread
    N= N number (development)
    ...QUOTE]

    Let's see: I have a scene with a spread from EV3 to EV17, that's a spread of 14. I developed it to N-3 or something like that - compensating developer by inspection so I don't really know.

    SBR=(7*(14-(-3))/14) gives 17/2, or 8.5

    Another scene, EV4 to EV6 (flat and dim), given a N+2 development:

    SBR=(7*(2-2))/2 is 0?

    Sorry, the formula doesn't work as written...
    Ole,

    A thought that may apply to this particular set of examples...I believe that you will find that the formula is accurate for SBR readings above 5. However below five I think that the adjustment that Sandy mentioned elsewhere may be appropriate. That would indicate that for SBR below 5 would indicate to subtract the measurement from 5 and in that event your correct SBR on your low contrast scene would be SBR 3.

    Jorge, I would like your thoughts on this as well.

  5. #65

    Join Date
    Mar 2003
    Location
    Greenville, SC
    Shooter
    Large Format
    Posts
    4,813
    Images
    5
    Quote Originally Posted by jdef
    I made a simple post and Donald Miller decided to interject his "expertise" on the subject to tell me how wrong I was, and was soon followed by Jorge and Sandy. At least Sandy refrained from personal attacks, unlike Jorge and Donald.
    Jay
    Jay,

    What is that all about? I did not have any part of the exchange you had with Donald and Jorge.

    Sandy
    Last edited by sanking; 04-17-2005 at 02:12 PM. Click to view previous post history.

  6. #66
    Stephen Benskin's Avatar
    Join Date
    Jan 2005
    Location
    Los Angeles
    Shooter
    4x5 Format
    Posts
    1,218
    Quote Originally Posted by sanking
    Jay,

    What is that all about? I did not have any part of the exchange you had with Donald and Jorge.

    Sandy
    I believe Jay meant the thread went off topic.

  7. #67

    Join Date
    Mar 2003
    Location
    Greenville, SC
    Shooter
    Large Format
    Posts
    4,813
    Images
    5
    Quote Originally Posted by jdef
    I know Sandy, and I acknowledged as much. I only included you because you also posted that I was wrong for using SBR as a function of development, and I know that both Donald and Jorge consider you an authority on BTZS, and rightly so. My point is that not one of the experienced BTZS users was willing to give me the benefit of the doubt long enough to consider what I was saying, or to even consider the possibility that there might be some merit to my point.

    I just think that as an acknowledged authority on the use of BTZS, you might have looked a little closer at the question before making the kinds of absolute statements that you did. Just to be clear, I do NOT group you in with the likes of Donald and Jorge. I respect your opinions and value your input, which is why I hold you to a higher standard than Donald or Jorge.

    Jay
    Jay,

    But where did I post that you were wrong to use SBR as a function of development? As I stated, I did not join in the exchange between you, Donald and Jorge in any way and I don't remember ever saying anywhere that it is wrong to consider SBR as a function of develoment. I am not sure that I would call SBR a function of development, but there is certainly a correlation between time of develoment and SBR, as anyone who has done any film testing and plotting knows.

    Perhaps you are confusing something I said on another thread? I do recall saying something on another thread to the effect that SBR refers to subject lighting conditions and is not dependent on exposure and develoment but I certainly did not mean that to understand that there was no correlation between time of development and SBR. In that statement I was simply trying to differentiate SBR from CI in that SBR is a measure of subject contrast whereas CI is a measure of contrast in the negative.

    Sandy
    Last edited by sanking; 04-17-2005 at 08:15 PM. Click to view previous post history.

  8. #68

    Join Date
    Dec 2002
    Shooter
    Large Format
    Posts
    6,242
    Jay,

    You appear to have made some allegations of things that I said within this thread, at least I read your post to indicate that. I would really appreciate it if you would point out what it was that I said and when I said it in this thread.

    I still don't think that SBR is a function of development, just as Sandy King recently reitterated once again. However, I don't believe that I ever indicated that there was no correlation.

    I look forward to your response.

    Donald Miller

  9. #69

    Join Date
    Sep 2002
    Shooter
    Large Format
    Posts
    4,530
    Quote Originally Posted by jdef
    Unfortunately, I think this thread was doomed from the beginning by the acrimony carried over from the BTZS and low contrast scenes thread. I made a simple post and Donald Miller decided to interject his "expertise" on the subject to tell me how wrong I was, and was soon followed by Jorge and Sandy. At least Sandy refrained from personal attacks, unlike Jorge and Donald. You guys have curious way of helping out a newcomer to the BTZS. In the end, a few things were cleared up for me despite the very negative tone of the discussion, thanks in part to Jorge for going to the source and consulting Phil Davis, even though I'm sure he was disappointed that Davis confirmed my position on SBR as a function of development. Thank you to all of you who have contributed to this thread in the spirit of mutual respect and for sharing your considerable knowledge and experience.

    Jay
    Aww men, I put this thread on ignore. Out of curiosity I check it out and nothing has advanced or improved.

    Now jdef, you are congratulating yourself too much. As Phil said, for a fixed ES , SBR can be targeted for development. You never mentioned this until I posted Phil's response. In fact as I had stated the more apropriate way to target development is G bar, because as he said, you dont have to specifically state ES or SBR.
    So, no, Phil's response did not "support" your contention. I would say that if we are going to keep score as you seem to want to do, it supported my position and the position of those who disagreed with you more than yours.

    As to the previous thread, I was no more insulting than you were. I tried posting in this thread an contribuite hoping that we could have a real discussion, but it seems you are more interested in "being right" than in having a real discussion. YOu are the one continuing bickering, keeping "score" and insinuating your "expertise". For someone who calls himself a "beguinner" you certainly act like you know it all.

    Next time, if I post a response from Phil, please read all of it, not just the parts you want to read. Unless you think you know more than Phil, you certainly behave that way....

  10. #70

    Join Date
    Sep 2002
    Shooter
    Large Format
    Posts
    4,530
    [QUOTE=Donald Miller]
    Quote Originally Posted by Ole

    Ole,

    A thought that may apply to this particular set of examples...I believe that you will find that the formula is accurate for SBR readings above 5. However below five I think that the adjustment that Sandy mentioned elsewhere may be appropriate. That would indicate that for SBR below 5 would indicate to subtract the measurement from 5 and in that event your correct SBR on your low contrast scene would be SBR 3.

    Jorge, I would like your thoughts on this as well.
    There has been a continuing misinterpretation that N- numbers are equivalent to numbers above 7 in the BTZS notation. This is incorrect, for example an N-2 number is not equivalent to targeting a G bar corresponding to an SBR of 9. Depending on the ES of the paper a G bar corresponding to an SBR of 9 might be anywhere from N-1 to N-3. WIthout knowing the paper Ole is using it is impossible to tell if the SBR number obtained by the formula is correct. Even so, I have to agree with Ole that for that extreme range the formula seems to be off, unless we are thinking that the formula assumes an ES of 1.05 for silver paper. Nevertheless this seems to be too big an assumption to make.

    As to the N+2 example, I think this is an unrealistic example. Anything having an EV of 4 I dont think will have enough light to have a highlight giving an EV of 6. If anything I think a closer number for the highlight would have been 4.5 or 5.

    You make a good point that it is possible this formula was created for SBR numbers of 5 and above, being that the BTZS was not initally designed for lower than 5 SBRs. I got the formula direct from Phil and it is also in the apendix of the books, at least it is in my second edition.

    In any case, you all dont have to take my word for it. Phil is always willing to answer questions at the BTZS web site. If this is a really important point for any of you I suggest you ask him directly.

Page 7 of 8 FirstFirst 12345678 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin