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Thread: Software rather than center filter for correcting illumination falloff?

  1. #1

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    Software rather than center filter for correcting illumination falloff?

    Does anyone know if there is a software application (since I scan my 4x5 negs) that would allow correction of wide angle falloff instead of using a ND Center filter?

  2. #2
    Tin Can's Avatar
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    Re: Software rather than center filter for correcting illumination falloff?

    At least a dozen ways with Photoshop

    and easy with an optical enlarger or even a contact print

    All basically the same concept as center filter
    sin eater

  3. #3
    Peter De Smidt's Avatar
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    Re: Software rather than center filter for correcting illumination falloff?

    These are post capture, though. If your film's range doesn't capture good tonal definition throughout the picture, then post work won't replace the filter. With bw (and enough exposure), you should be fine. It might be more of a problem with color transparencies.
    “You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
    ― Alexander Den Heijer, Nothing you don't already know

  4. #4

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    Re: Software rather than center filter for correcting illumination falloff?

    The easiest way to do this in software (in my opinion) is the post crop vignetting tool in the Photoshop's Camera Raw app. I will note that sometimes its okay leave some light falloff in a wide angle shot, so don't overdo the correction.

  5. #5
    Alan Klein's Avatar
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    Re: Software rather than center filter for correcting illumination falloff?

    Is there a list of lenses that have this problem? I just started 4x5 photography and have a Schneider Kreuznach Apo Symmar 150mm F_5.6 MC. I shoot chromes and BW.

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    Re: Software rather than center filter for correcting illumination falloff?

    Quote Originally Posted by Alan Klein View Post
    Is there a list of lenses that have this problem? I just started 4x5 photography and have a Schneider Kreuznach Apo Symmar 150mm F_5.6 MC. I shoot chromes and BW.
    Super Angulons, Grandagon, WA Nikkor, WAFujinons and Symmar XL as well as all other wide angle designs that look like these lenses.

  7. #7
    Peter De Smidt's Avatar
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    Re: Software rather than center filter for correcting illumination falloff?

    Alan, you won't need a center filter with that lens.
    “You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
    ― Alexander Den Heijer, Nothing you don't already know

  8. #8

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    Re: Software rather than center filter for correcting illumination falloff?

    Quote Originally Posted by Alan Klein View Post
    Is there a list of lenses that have this problem? I just started 4x5 photography and have a Schneider Kreuznach Apo Symmar 150mm F_5.6 MC. I shoot chromes and BW.
    Alan, the usual recommendation is that lenses that cover at least 90 degrees should be used with a center filter. See http://www.galerie-photo.com/center-...at-lenses.html

  9. #9

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    Re: Software rather than center filter for correcting illumination falloff?

    With Photoshop the easiest way:
    open the image file.
    filter>Lens correction
    choose custom and not auto-correction
    using the vignette tool slider, move it to the right ("lighten")
    sometimes works with B&W amazingly well, have never found it to work well with color

    There are many other ways to do this in Photoshop, but you will have to customize your technique for each of your lenses. I shot a B&W with my 65mm of an 18% gray card and scanned the negative. There was illumination falloff which I corrected in Photoshop till the image was as even as I could get it using the window>info measuring tool. But the correction will differ with each of your lenses requiring you to create a different "digital illumination falloff corrector" correction mask (if you want to call it that). In the end though I now either just accepted the illumination falloff or use a center ND filter.

  10. #10
    Tin Can's Avatar
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    Re: Software rather than center filter for correcting illumination falloff?

    OK, now we seem to have all players present

    Who has the very rare and expensive Center Filters?

    What lens do you use on it on?

    Will you post images made with and without on lens CF as exposed filters? (meaning no correction in post optical or PS)

    and did NIKON ever sell CF for their lenses? Why not?

    Nikon LF Lens Brochere from Ken Lee http://www.kennethleegallery.com/pdf...rmatLenses.pdf
    sin eater

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