IR Cutoff Filter Question

Discussion in 'Digital Photography' started by 1251division, Apr 28, 2014.

  1. 1251division macrumors member

    Joined:
    Oct 8, 2012
    #1
    I have a question for the group:

    I have a UV/IR Cutoff filter, and when first using it, noticed that I was getting blue/green fringing along the edges of the frame. (See attached photos--these are unedited camera RAW-->JPEG via LR). I suppose this is normal, as the IR Cutoff tends to block the longer wavelength visible red light as well. (Note that the first image is shot into the light, and the 2nd at ~90-deg, with sun directly overhead.)

    I am wondering:
    a) what is the best--or typical--use of this filter
    b) is there any way to correct this issue?​


    I think it can be used for artistic effect, but I am looking for a clean image.

    Thank you!

    P.S. Here is a link to the filter:
    http://www.promaster.com/products.asp?product=DUVIRCUT
     

    Attached Files:

  2. themumu macrumors 6502a

    themumu

    Joined:
    Feb 13, 2011
    Location:
    Sunnyvale
    #2
    That's not fringing, that's full on colour cast! Even the product photos on that website are showing very strong colour shift near the edges of the filter.

    To be honest, I've never heard of this particular brand, and I'm torn as to whether they do this effect on purpose, or if you got a defective filter. They do claim that using their filters will give you "sharpener and clearer images", and I'm always suspicious of commercial websites with spelling errors ;)

    Personally I use a Hoya UV filter, but only to protect the front element from dirt, I have never been able to detect any improvement in sharpness or what not. I don't think there is any point in using anything extra to block IR light, as the modern digital cameras tend to come with very aggressive IR filter already, mounted directly over the sensor.

    I was gonna say something like, cheap filters tend to degrade image quality, no matter how good they claim to be, but these are actually on the expensive side, yet still apparently suck. Try shooting the same scene with and without a filter (with a tripod) and see which offers "greater detail, more natural colors and finer colour gradation".

    My guess is that to correct the issue you are having with blue/green cast you simply need to remove the filter.
     

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