zone system test with filter on lens?

Discussion in 'Darkroom Developing and Printing' started by Phil Lamerton, May 17, 2004.

  1. I'd like to photograph a gray card outside on an overcast day, in
    order to do some zone system testing with my new camera and lenses.

    Since I will eventually be using the camera in the portrait studio
    with a yellow/green filter, would it be wrong to do the testing with
    the filter over the lens?

    Thanks in advance for your advice on this.

    phil lamerton
     
    Phil Lamerton, May 17, 2004
    #1
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  2. Phil Lamerton

    Nick Zentena Guest


    Are you doing a film speed test? If you intend to use the filter nothing
    wrong with testing with the filter on. It'll give you a more accurate result.

    Nick
     
    Nick Zentena, May 17, 2004
    #2
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  3. I agree,....its the best method for absolute testing.
    --
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    Gregory W Blank, May 18, 2004
    #3
  4. Phil Lamerton

    CWal871581 Guest

    HREF="http://members.verizon.net/~gregoryblank">http://members.verizon.net
    /~gregoryblank</A>


    If the yellow filter was put on and zones I to X were shot (at the EI
    determined
    by a no filter test), and then the film was processed using what the no filter
    test determined to be the correct time and agitation, what is the predicted
    change in the density in the shots that used the filter?

    TIA,
    Curtis
     
    CWal871581, May 18, 2004
    #4
  5. You can use a mathmatical formula to determine the approximate
    density but using the filter and reading each zone or steps on a wedge
    etc is prbably more accurate.
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    Gregory W Blank, May 18, 2004
    #5
  6. At the risk of incurring the rath of the previous responders, No, what you
    propose is not a good idea.

    The basic idea of testing the film speed, zone testing, etc, with the filter
    in place is fine.

    Doing the testing in overcast daylight where the planned use is in studio,
    under tungsten or electronic flash, is a bad idea because the color
    temperature of overcast daylight is much higher than anything you will use
    in the studio. The studio response of the film/filter combination will be
    quite different than your testing experioence, rendering the point of your
    testing largely irrelevant.
     
    Randy Stewart, May 18, 2004
    #6
  7. Actually your correct and that should have been noted by the rest of us.

    & to the O.P.

    In order to obtain accurate results you have to test the film under the same
    conditions you wish to use it.
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    Gregory W Blank, May 18, 2004
    #7
  8. What 'camera and lenses'?
     
    Michael Scarpitti, May 18, 2004
    #8
  9. At the risk of incurring the rath of the previous responders, No, what you
    Thanks for this info. Please could you explain a bit more?

    If I calculate the film speed and development time for N using my
    outdoor results, will the difference indoors with electronic flash (or
    tungsten) be so significantly different that the results will be
    unusable, given that contrast can be controlled in the studio?

    By how much would the color temperature outside differ from my
    electronic flash, and by how much do you think it would throw out the
    speed test & development time results on black & white film?

    I suppose I could light the gray card indoors with an electronic
    flash. Will it not matter that I shall subsequently use varied
    lighting set-ups (and number of lights).

    TIA

    regards, phil lamerton
     
    Phil Lamerton, May 18, 2004
    #9
  10. How would it affect your answer if you knew the camera and lens in
    question? Most filters work quite similarly no matter what camera or lens...
     
    Severi Salminen, May 18, 2004
    #10
  11. Remember that you need a spot meter capable of reading flash light (not
    every meter can do it) if you intend to use ZS in studio with normal
    eletronic flashes. ZS is of quite limited use with an incident flash meter.

    Severi S.
     
    Severi Salminen, May 18, 2004
    #11
  12. Koni Rapid Omega with 90mm and 180mm lenses. I'm uncertain as to why
    you should ask this?

    rgds, phil lamerton
     
    Phil Lamerton, May 18, 2004
    #12
  13. It matters a great deal. Is this medium format? Large format? 35mm?
     
    Michael Scarpitti, May 18, 2004
    #13
  14. Umm, how does it matter? Does light behave differently between various
    formats? Does a certain filter affect light differently on different
    camera body?

    Let me ask like this:

    1. Would it be wrong to do the testing with the filter over the lens
    using (35mm) Canon EOS 30 with a 50mm f/1.8 lens?

    2. Would it be wrong to do the testing with the filter over the lens
    using (6x7) Mamiya RB 67 Pro-S with a 180mm f/4.5 lens?

    3. Would it be wrong to do the testing with the filter over the lens
    using (4"x5") Toyo Field 45AII with a Schneider 150mm f/5.6 lens?

    How would the answers now differ? In what cases it _IS_ wrong to do the
    testing with filter in place? And why is it wrong? I'm just curious to know.


    Regards
    Severi S.
     
    Severi Salminen, May 18, 2004
    #14
  15. Phil Lamerton

    Frank Pittel Guest

    : (Phil Lamerton) wrote in message : > I'd like to photograph a gray card outside on an overcast day, in
    : > order to do some zone system testing with my new camera and lenses.
    : >
    : > Since I will eventually be using the camera in the portrait studio
    : > with a yellow/green filter, would it be wrong to do the testing with
    : > the filter over the lens?
    : >
    : > Thanks in advance for your advice on this.
    : >
    : > phil lamerton

    : What 'camera and lenses'?

    What difference could the camera or lens possibly make?
    --




    Keep working millions on welfare depend on you
     
    Frank Pittel, May 19, 2004
    #15
  16. Phil Lamerton

    Frank Pittel Guest

    : Michael Scarpitti wrote:

    : >>>What 'camera and lenses'?
    : >>
    : >>How would it affect your answer if you knew the camera and lens in
    : >>question? Most filters work quite similarly no matter what camera or lens...
    : >
    : > It matters a great deal. Is this medium format? Large format? 35mm?

    : Umm, how does it matter? Does light behave differently between various
    : formats? Does a certain filter affect light differently on different
    : camera body?

    : Let me ask like this:

    : 1. Would it be wrong to do the testing with the filter over the lens
    : using (35mm) Canon EOS 30 with a 50mm f/1.8 lens?

    : 2. Would it be wrong to do the testing with the filter over the lens
    : using (6x7) Mamiya RB 67 Pro-S with a 180mm f/4.5 lens?

    : 3. Would it be wrong to do the testing with the filter over the lens
    : using (4"x5") Toyo Field 45AII with a Schneider 150mm f/5.6 lens?

    : How would the answers now differ? In what cases it _IS_ wrong to do the
    : testing with filter in place? And why is it wrong? I'm just curious to know.

    It would be wrong for you to use any camera but a leica.
    --




    Keep working millions on welfare depend on you
     
    Frank Pittel, May 19, 2004
    #16
  17. 1. First of all, because zs is unsuited to roll film.

    2. Because some cameras have the shutters in the lenses, and thus each
    lens has to be calibrated.

    3. Because leaf shutters are less efficient at high shutter speeds and
    large apertures. It takes time for the blades to open all the way, and
    thus the full aperture is not available during the entire exposure. At
    lower shutter speeds and small apertures, the percentage of time
    during which the entire aperture is used is much higher. Electronic
    flash is so quick that this does not matter, and thus your exposure
    will not be the same.


    In addition:
    Reciprocity failure may affect flash pictures differently than normal
    shutter speed images.
     
    Michael Scarpitti, May 19, 2004
    #17
  18. Actually ZS is very usable with roll films. There are of course some
    limitations as per frame development is quite difficult to do but ZS can
    be used (at least to some extent) with roll film cameras. And in studio
    environment (as in Phil's case) it is quite easy to have and change
    different backs/rolls for different development times. But Phil
    obviously didn't ask if ZS is suitable or not, but about using a filter
    when testing.
    But that has nothing to do with Phil's question about testing with
    filter in place. It doesn't even matter if one uses ZS or not: the
    photographer should allways know the accuracy of his/her shutters.
    Otherewise it is quite hard to make correct exposure with _any_ technique.

    Focal plane shutter is not allways a solution as aperture blades/scale
    can also be a bit off. So some basic testing is allways beneficial.
    That is true - allthough the difference might or might not be of any
    importance. But that is a phenomenon that must be considered allways.
    Phil asked only about testing with/without a filter - which you didn't
    even bother to answer :)

    Regrads
    Severi Salminen
     
    Severi Salminen, May 19, 2004
    #18
  19. Thanks very much for all the advice.

    Please could anybody clarify something? If I calculate my film speed
    and development time for N outdoors, with the filter in place (and for
    each of my lenses), how different are the results likely to be from
    those of the same test conducted indoors using electronic flash
    lighting?

    Also, in studio portraiture I am unlikely to place any essential part
    of the image on the toes region of the film's characteristic curve.
    Doesn't this mean I could safely use the film speed determined in my
    outdoor test?

    TIA - phil lamerton
     
    Phil Lamerton, May 19, 2004
    #19
  20. The filter bit is actually irrelevant, or at best, the least of his
    worries, but he was unaware that these other issues will mess up his
    measurements completely.

    Why?
    1. An electronic flash exposure make with a leaf shutter does not
    suffer from inefficiency. All shutter speeds will give the same
    exposure (not counting ambient light) with electronic flash.
    Existing-light exposures made with different combinations of apertures
    and shutter speeds, using a leaf shutter, will not be equivalent,
    because slow speeds and small apertures will give more total exposure
    than the nominally equivalent exposure with large apertures and high
    shutter speeds.

    2. A certain amount of reciprocity failure is possible with electronic
    flash, the duration of which is often much less than daylight
    exposures.
     
    Michael Scarpitti, May 19, 2004
    #20
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