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Thread: Question re IR Filters

  1. #1

    Question re IR Filters

    Hello, my name is Russ from Hampton, VA USA.
    I am interested in learning about IR filters which are an integral part of certian CCD
    designed digital cameras. Is there anyone in the forum space who is familiear with
    the technical specifics of such imbedded internal lenses? I am doing very high temp.
    photography and need to learn how to modify, and or replace/specify, the wavelength
    of the IR lens filter to suite my photos.
    Thanks u very much and nice to be a part of this forum group.
    Regards
    Last edited by Donald; 1st February 2011 at 05:32 PM. Reason: Copied from 'New Members' thread

  2. #2
    Moderator Donald's Avatar
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    Re: Question re IR Filters

    Russ

    As advised in the 'New member' thread, hopefully more members will see your question here and you will get responses.

  3. #3

    Re: Question re IR Filters

    Quote Originally Posted by Donald View Post
    Russ

    As advised in the 'New member' thread, hopefully more members will see your question here and you will get responses.

  4. #4

    Re: Question re IR Filters

    Thanks Donald, good to be a part of the group.
    I am a researcher and tend to have rather esoteric/highly detailed issues that I'm trying to deal with.
    I would consider myself pretty much a novice at photogrammetry, but I'm trying to come up to speed quickly.
    I have already figured out my wavelength spectrum for IR (with associated temps) and they are:
    Near infrared - 873F-4941F @ 1000nm-5000nm
    Mid infrared - -207F-873F @ 5000nm-40,000nm
    Far infrared - -438F to -207F @ 40,000nm-350,000nm (I like to keep the units the same as for the visible spectrum for comparisson purposes).
    My principal focus is in the near infrared spectrum (and a wee tad in the mid infrared).
    However, I still have yet to figure out the IR lens technicals with respect to a CCD sensing element.
    I conjecture that such an embedded lens would have to cover a range of wavelengths, most likely pegged to
    the temperature of the subject that is being captured by the digital camera.
    I greatly appreciate any help that I can get from your user community.

  5. #5
    Steaphany's Avatar
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    Re: Question re IR Filters

    Russ,

    I recommend that you check out Life Pixel Infrared, they are a company that offers a service of replacing a camera's internal IR blocking filter with an IR band passing filter.

    I'm sure they would be able to get a camera to operate as you require

  6. #6
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    Re: Question re IR Filters

    It is possible to have a camera converted to IR. I know of two correspondents who are using modified cameras in combat zones. It is not difficult from your end, just a little costly.

    http://www.digitalsilverimaging.com/...FQIBbAodkQmP0g
    http://www.lifepixel.com/IR.htm

    Pops

  7. #7

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    Re: Question re IR Filters

    Quote Originally Posted by RocketRuss View Post
    Thanks Donald, good to be a part of the group.
    I am a researcher and tend to have rather esoteric/highly detailed issues that I'm trying to deal with.
    I would consider myself pretty much a novice at photogrammetry, but I'm trying to come up to speed quickly.
    I have already figured out my wavelength spectrum for IR (with associated temps) and they are:
    Near infrared - 873F-4941F @ 1000nm-5000nm
    Mid infrared - -207F-873F @ 5000nm-40,000nm
    Far infrared - -438F to -207F @ 40,000nm-350,000nm (I like to keep the units the same as for the visible spectrum for comparisson purposes).
    My principal focus is in the near infrared spectrum (and a wee tad in the mid infrared).
    However, I still have yet to figure out the IR lens technicals with respect to a CCD sensing element.
    I conjecture that such an embedded lens would have to cover a range of wavelengths, most likely pegged to
    the temperature of the subject that is being captured by the digital camera.
    I greatly appreciate any help that I can get from your user community.
    I assume from your use of temperatures linked to wavelength that you are mainly interested in infrared emission. If you are using the near to mid infrared range, wouldn't you be better off looking at thermography or thermal imaging?

    (For the low temperature/far infrared there's a whole lot of other problems related to emission from the equipment, requiring fairly sophisticated cooling arrangements with liquid nitrogen or liquid helium, definitely outside the focus of this site).


    Afaik, the kind of infrared photography you see on this site mainly uses the reflected near infrared from sunlight (green leaves aren't anywhere near 800F/400C), not emitted infrared.

    Remco

  8. #8

    Re: Question re IR Filters

    Thanks, I will check them out.
    R

  9. #9

    Re: Question re IR Filters

    Thanks Pops.
    I'm not convering over to a fully IR camera, I just need to understand
    the specifics of what kind of IR lenses are already embedded in a
    digital camera (normal digital camera's don't have such lenses, but
    many high end apps need such an element).
    Regardless, thank you for your response and I will check out the links that you
    sent me.
    Regards - RR

  10. #10

    Re: Question re IR Filters

    Thanks Remco.
    Our current approach utilizes high end DCs in the visible spectrum but using an IR camera
    as the main sensor has occured to us, but it's not feasable at this point
    (the software that we are using won't interface properly with it).
    Regards - RR

  11. #11

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    Re: Question re IR Filters

    The IR blocking filter in modern cameras is mostly there to prevent the sensor picking up any IR light because it is out of focus compared to visible light. This causes a softening of the final image. Also, due to temperature issues, there is some small amount of IR given off by the internal components of the camera.
    Not knowing what you are doing with the camera, its difficult to suggest a way forward, but guessing that you want to image things at high temperature, might I suggest a camera without a filter? Astrophotography uses cameras with no IR (or UV) filtering, so that may be a way forward. They come without a lens, but they're easy enough to come by. Here's a link:-
    http://www.atik-cameras.com/html/cameras.html

    Another possible is to take the IR filter out of a webcam. Cheap solution, but easy to interface to a PC.

    Please let us know what you are doing as I have a slight professional interest here.

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