how a normal digital camera captures IR pictures with visible vein?

Discussion in 'Mirrorless Digital Cameras' started by alan_wang|1, Mar 21, 2004.

  1. hi guys,
    I'm sort of new to IR photography. I wanna use my Canon A80 to
    capture some IR images. But when I tried the Hoya R72 filter in the
    shop, there's no diplay on my camera screen except for the very
    bright spot light. I wonder how you guys take IR pictures if it can
    only capture the bright spot light?
    besides, in the previous post (http://www.photo.net/bboard/q-and-a-
    fetch-msg?msg_id=007ELI), it says we can capture under skin vein with
    the digital camera and IR filters. sorta quite curious to it. How to
    do that?
     
  2. You need long esposures. Some digital cameras have harsh hot mirrors that really spread IR and make them less suitable for IR photography. I don't know whether the A80 is one of these.
     
  3. yeah, but I tried it in front of a TV remote. there was a bright spot on the screen of the Canon A80. Does that mean I can use it to capture IR images too?
     
  4. how can i used my canon S50 captured Infra Red Image can take picture throught cloth?
     
  5. All digital cameras have an internal IR-block filter in front of the sensor. Its purpose is to reject infrared energy from hitting the sensor - which is naturally sensitive to IR as well as visible light. A couple of cameras have a mode that will flip this internal IR-block filter out of the way. The sony f707/717/828 cameras have this feature. This permits taking IR pix at normal exposures. You do need to screw on an IR-pass filter, though, to reject visible light. If your camera does not flip the IR-block filter out of the way, it will be difficult to achieve good results.
    [​IMG]
     
  6. I tried IR photos with my D300, but internal IR filter prevented usable results. For some reason, it did capture my TV remote. Maybe it runs at a part of the spectrum that is not blocked by the filter.
     
  7. It's completely doable, and the A80 is great because it has the filter adapter.

    When you put the R72 filter on (I use it on my Canon G3) don't expect to see much inside, there's not a whole lot of IR in there. However if you go outside the view on the LCD should be quite fascinating. You can use this to compose and auto focus and autoexposure will work (the camera just bumps up sensitivity on the CCD).

    On my G3 in full bright sunlight I get exposures of roughly 2-4 seconds, I suspect the A80 may be the same.
     
  8. You took a picture of your IR remote and only got a spot? That at least confirms that the IR filter in front of your sensor will let IR through. You need to not take pictures of IR LEDS. Go outside on a sunny day with clouds and take some pictures.
     
  9. sounds like it's possible for canon A80 to take IR pictures. thanks guys. I will try it out. But what about the vein thing? did anyone try to capture this kinda pictures? Is there any special requirement on it?
     
  10. Older digital camera backs have no IR filter. One has to place a special "hot mirror" IR absorbing filter over the taking lens. Without the IR adsorbing filter; the digital back collects both visible and IR. My older Phase One 4x5 digital back is like this.
     
  11. Given the IR-removing filter, shooting IR requires a lot of light with a typical digicam and some cameras do it better than others. I've been successful with an Olympus C-5060 with a Heliopan 715 (Wratten #88 equivalent), but I'm still working on my technique - there are challenges.

    Kelly: such a back would be way cool, especially if it can be mounted on a view camera and has sufficient resolution.
     
  12. All the digicams I have come across see TV remotes so I am not sure how this test began. I have a Canon G2 . Taking digital pictures with this gives slightly blurry results with a very visible hot spot. Not ideal though it sees remotes well enough.
     
  13. Does it need to be infrared or do you want a picture to make the vein seem prominant.

    If you just want the vein to stand out from the background, put a torniquet on the arm and use a filter to promote the blue colour of the vein. Desaturate the image and you should have what you are after.

    Pick a male arm as the veins are usually larger.


    Peter
     

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