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  1. #1

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    f-stop printing calculations

    What is the formula that is used to calculate the times shown in the various f-stop printing sheets?

    For example
    If the base time is 8 sec:
    +1 stop = 16 sec how do you arrive at +1/2 stop = 11.3 sec?

    Todd

  2. #2
    Bruce Osgood's Avatar
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    Quote Originally Posted by Todd Barlow
    What is the formula that is used to calculate the times shown in the various f-stop printing sheets?

    For example
    If the base time is 8 sec:
    +1 stop = 16 sec how do you arrive at +1/2 stop = 11.3 sec?

    Todd
    ------------------------------------------------------------

    http://unblinkingeye.com/Articles/Te.../testexpo.html

    This should give you a good starting point.

  3. #3
    Lee L's Avatar
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    Todd,

    I made up my own tables in a spreadsheet. If you can handle openoffice or Excel spreadsheets, the attached .zip file has both formats (done in openoffice) that produce an f-stop printing table. You can look at the formulae used in the spreadsheet to get an idea of how it works.

    I just taught two 6th graders the basics of B&W, and since they'd just learned the basics of geometric progressions with camera stops and shutter speeds, f-stop printing seemed very natural and logical to them. I now use an RH Designs timer rather than these charts.

    Lee
    Attached Files

  4. #4

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    Thanks Lee, that is great. Helps us what got problems with cypherin.

  5. #5
    lee
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    RH Designs Stopclock timer will do this for you and is much more accurate but the trade off is it is more expensive.

    lee\c

  6. #6
    Marc Leest's Avatar
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    Quote Originally Posted by Todd Barlow
    What is the formula that is used to calculate the times shown in the various f-stop printing sheets?

    For example
    If the base time is 8 sec:
    +1 stop = 16 sec how do you arrive at +1/2 stop = 11.3 sec?

    Todd
    Simple

    it would be T x 2^+f
    (^ means to the power)
    So in your example
    it would be
    8 x 2^ +1 = 16
    8 x 2^+0.5 = 11.31

    M.
    We cannot change how the cards are dealt, just how to play the hand...
    Randy Pausch

  7. #7
    Lee L's Avatar
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    For those without a spreadsheet program, an f-stop timing table for printing is at: http://www.largeformatphotography.in...pTimingAdv.pdf
    This is a .pdf file of a page from Way Beyond Monochrome.

    I didn't mention it in my earlier post, but openoffice is free and very capable, and available for Windows, linux, solaris, BSD, and Mac OS-X. See openoffice.org

    Lee

  8. #8
    PieterB's Avatar
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    Yes I saw the .odt in your zip-file
    "The camera can be the most deadly weapon since the assassin's bullet. Or it can be the lotion of the heart - Norman Parkinson".

  9. #9
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    Todd:

    Thanks for asking the question.


    Posters:

    Thanks very much for answering.


    Joe

  10. #10

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    Do a google, there are several places on the web where you can download the images to make a calculator. Or buy a new/used copy of the Kodak Darkroom Guide which has one.

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