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Thread: A Shot in the dark...

  1. #1
    Flashaholic*
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    Default A Shot in the dark...

    Not sure where to post this - so I it landed here...

    This pic was taken hand-held from about 15" with a Canon A80 of a TV remote control with the IR LED radiating energy...1 second manual exposure/f2.8/ISO400/AWB and little ambient light (twilight level)...



    So my question is...if I put an IR filter on a Tigerlight/Surefire/100W Spotlight, etc. can I radiate enough IR energy to take digital pics in the dark?

    I don't have an IR filter to try, but I'm hoping one of you out there might be able to tell me if it'll work...


    Thanks - John

  2. #2

    Default Re: A Shot in the dark...

    Probably not. The reason is most digital cameras have an IR filter to keep the color balance correct. (your shots end up looking weird colorwise if IR is let in)

    These aren't 100%, so you can still see remote control LEDs a little. But to get enough illumination beyond a point or spot given how much the IR lens is filtering out is difficult.

    There are quite a few digital cameras that are easy to use with IR, I'm not sure if yours is one of them or not. I know some of the more popular ones are Sonys with nightshot, where the camera moves the IR filter out of the way.

  3. #3
    Flashaholic*
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    Default Re: A Shot in the dark...

    My camera has a custom white balance mode - normally intended for use with a photo quality grey card or a white sheet of paper. I wonder If I can "fool" it using this feature...

    This camera also has a "night shot" mode where the flash is used to illuminate the subject and the shutter is held open longer to allow darkened background to show (i.e. overlook with city lights in background). IR filter??? - Dunno

    Thanks for the reply - John

  4. #4

    Default Re: A Shot in the dark...

    The white balance wouldn't effect it... it may be possible that the filter is mechanically moved for the night shot mode as it is in the Sony cameras, but I could not find any information on the Canon website or Google to support this. Is the remote any brighter with the "night shot" mode enabled?

    If not, your camera has a limited ability to see IR. You can disassemble it and remove the filter yourself, or get a really, really, really bright IR source that would make enough light go through the filter :P.

    A good "ghetto" flashlight IR lens filter is a stack of developed but not used film negatives. Incandescants will work best an IR source. (only 3% of an incandescant's output is visible light iirc)

    If all else fails, you can throw your camera on ebay and buy a Sony F-717 [img]/ubbthreads/images/graemlins/smile.gif[/img]

  5. #5
    Flashaholic*
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    Default Re: A Shot in the dark...

    OK,

    Thanks for the info...

    The A80 seems to be a nice camera for the price I paid - I'll likely keep it. While I don't have a specific need for IR photo capabilities, I was just exploring some posibilities for fun with flashlights... [img]/ubbthreads/images/graemlins/smile.gif[/img]

    Thanks again - and Have a Safe & Merry Christmas!

    John

  6. #6
    Flashaholic*
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    Default Re: A Shot in the dark...

    Illuminated,

    Your camrea's "night shot" mode probably does not remove the IR filter from the optical path. This is most likely a long exposure mode that, while useful for low light photography, may not work well with IR.

    For reference, I can perform the same test with my Sony DCR-TRV33 camcorder (which has a "NightShot" mode which really does remove the IR filter) and in NightShot mode the LED easily completely blinds the image sensor, while in normal mode it looks similar to the picture you took--thus demonstrating how much IR is filtered out.

  7. #7
    Flashaholic*
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    Default Re: A Shot in the dark...

    Yes, I have determined that my camera does not remove the IR filter from the optical path. At least I learned something I did not know before [img]/ubbthreads/images/graemlins/smile.gif[/img]

    Thanks - John

  8. #8
    Enlightened Shredhead's Avatar
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    Default Re: A Shot in the dark...

    hey where are the images??

  9. #9
    Unenlightened
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    Default Re: A Shot in the dark...

    Just tried this with my old Canon UC10.
    I used my IR spotlight to illuminate a dark area. when viewed with the camera, light was apparent, but not much. Wavelength about 850nm. So my cam must have an aggressive IR filter.

    Steve

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