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  1. #1

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    Using calculators for photographic ends

    Rereading the thread I started on reciprocity of available sheet films, I started thinking about using a calculator for other purposes related to photography. For instance, after calculating reciprocity failure, one could then run a count-down timer to time the exposure. Another use might be to calculate f-stop timing intervals from a spreadsheet or matrix of pre-existing numbers. Say enter 6 seconds at the minimum time and 12 as the end time, with 1/4 stop intervals, produces a list; 1.9, 1.6, 1.4, 1.1, 6. etc.

    Would those with more experience in using programmable calculators care to comment on these thoughts?

    Tom.

  2. #2
    BradS's Avatar
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    I regularly use an ordinary pocket calculator (HP-32s) to compute bellows factors. I guess I could write a short program to automate it somewhat...just never bothered.

  3. #3

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    I did a lot of high magnification work, and had a calculator always at the ready.
    Made a small computer program that did all the different calculations i need in one go.

    A version of that program, tailored to Zeiss/Hasselblad lenses, is online.

    Still want to port it to run on PDAs, but haven't gotten round to it.


    Reciprocity failure is to 'unruly' to capture in a calculator.

  4. #4

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    Good Morning,

    I use a calculator to determine changes in print-exposure times when I change sizes. Much of the time, experience gives me what I need, but the calculator provides reassurance.

    Konical

  5. #5
    Frank Szabo's Avatar
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    Quote Originally Posted by Q.G. View Post
    I did a lot of high magnification work, and had a calculator always at the ready.
    Made a small computer program that did all the different calculations i need in one go.

    A version of that program, tailored to Zeiss/Hasselblad lenses, is online.

    Still want to port it to run on PDAs, but haven't gotten round to it.


    Reciprocity failure is to 'unruly' to capture in a calculator.
    Can't be any worse than scratch-writing a Fortran program for Simpson's Rule and that's not difficult (assuming a suitable quantity of adult beverages) ...

    Couldn't reciprocity failure be expressed as one would a limit? (think beginnings of the calculus - not the stuff on one's teeth).
    Last edited by Frank Szabo; 05-20-2009 at 01:00 PM. Click to view previous post history.
    ...

    "Beer is proof that God wants us to be happy."

    Benjamin Franklin

  6. #6

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    Frank,

    See: http://www.apug.org/forums/forum37/6...eet-films.html - relating to the calculation of reciprocity failure.

    Tom.

  7. #7

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    Reciprocity is for each film diferent.
    I gues you are better of with a little cardboard with those data for the films you use most.

    Peter

  8. #8

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    Peter,

    In the thread I linked to Patrick Gainer discusses a formula for working out the needed increase in exposure to account for reciprocity failure, using a correction factor derived for each film type.

    Tom.

  9. #9

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    Quote Originally Posted by Frank Szabo View Post
    Couldn't reciprocity failure be expressed as one would a limit? (think beginnings of the calculus - not the stuff on one's teeth).
    The important bit in this reciprocity failure thing is expressed by the word failure.
    If there was an easy rule, an unequivocal relation, a simple formula, Bunsen and Roscoe would have found it ages ago.

    You can explore the behaviour of films, and compile tables.

    But - and this is important - you cannot (!) calculate reciprocity failure.

  10. #10

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    Ive written a few small ones as needed for my cell phone, as its usually always there and with me, and less to carry around to not need the calculator.



 

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