Filtering for Acros 100/

Discussion in '35mm Cameras and Accessories' started by chip j, Mar 8, 2014.

  1. chip j

    chip j Subscriber

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    I have recently read on this forum that Acros 100 is ortho, and also that it has extended red sensitivity. Whats' the truth?
     
  2. fretlessdavis

    fretlessdavis Member

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    To me, it seems slightly more Ortho than Delta or Tmax 100. It doesn't respond to a red filter very well-- skys don't get much darker, and green foliage just goes to pure black.... even going to a stop more than recommended filter factor. Other than that, for me at least, filters behave like they would on Delta or Tmax. If I want really dramatic skys, I'll stack a polarizer and a yellow or orange.
     
  3. kazuo

    kazuo Member

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  4. lxdude

    lxdude Member

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  5. Neal

    Neal Subscriber

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    Dear Chip j,

    Those two claims are contradictory. Generally, "ortho" films are only sensitive to blue and some green. Extended red sensitivity means that the film would record at least partially into the infra-red. That would be quite a problem for ortho films, particularly when you go to develop by inspection. :smile: What I think folks are getting at is that traditional films were, relatively, less sensitive to blue than red and therefore using a red filter would give you darker skies compared to the newest films (Acros/Delta/T-Max) which have a much flatter spectral sensitivity.

    Go with FP-4+ if you want that old sky look with finer grain.

    I think I added enough qualifiers in the above to wiggle out of trouble. :wink: Good luck,

    Neal Wydra
     
  6. pentaxuser

    pentaxuser Subscriber

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    Neal, I think you are saying that the trad grain films such as FP4 will give darker skies with a red filter and yet in the case of TMax Kodak states that it is less sensitive to blue giving darker blues( closer to how the eyes sees blue) so I'd presume that with a red the TMax skies should be darker

    In the Kodak quote however I don't think it says what it is less sensitive than. Is it FP4+, HP5+, Tri-X? It just doesn't say unfortunately

    pentaxuser
     
  7. StoneNYC

    StoneNYC Subscriber

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    FWIW I just did a comparison with a red filter of TMY-2 and FP4+ and the negs and (scanned) images look almost identical...

    Here are the results. Sorry not printed optically :sad: but thought it might be helpful to post none the less...

    FP4+
    ImageUploadedByTapatalk1394304396.919495.jpg
    TMY-2
    ImageUploadedByTapatalk1394304411.370825.jpg

    Both with red filter, both in DD-X both with exact same exposure (2 stop difference obviously).
     
  8. Neal

    Neal Subscriber

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    Hi Pentaxuser,

    If a film is less sensitive to blue than red, the unfilltered sky will be slightly less dense and appear slightly darker when printed.

    At least I think that's right.

    Neal Wydra
     
  9. Neal

    Neal Subscriber

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    Dear StoneNY,

    I believe you have clearly demonstrated that the vast majority the differences discussed is, for all practical purposes, picking the fly poop out of the pepper.

    Neal Wydra
     
  10. Fixcinater

    Fixcinater Subscriber

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    Thanks for posting this.

    Just to satisfy curiosity, did you set contrast (or: black and white points) equal to each other or to taste individually? The only "real" difference I see is the TMY-2 frame going a bit darker in the deep shadows, hence my question.

    Thanks again for the comparison.
     
  11. StoneNYC

    StoneNYC Subscriber

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    I essentially let the scanner do it's thing, but from my experience, in a given scene that is comparable, the scanner will give the proper comparison... This MIGHT help....


    Yellow filter
    ImageUploadedByTapatalk1394381961.222258.jpg

    Red filter
    ImageUploadedByTapatalk1394381982.638710.jpg

    To qualify, the clouds did change the exposure slightly and you can see the sky is more exposed in one as the sun "burst through" just as I was shooting, but relatively speaking I think this will be helpful to see as a reference, also obviously there's no accounting for differences in development times where I might have over developed, etc, still getting used to the rotary processor times.