Re: Infrared photography

Discussion in 'Digital Photography' started by nospam, Sep 25, 2008.

  1. nospam

    nospam Guest

    In article <>, bino
    <> wrote:

    > The problem is that you won't see an IR picture per se, as the image
    > requires post processing to be anything but a dark red image. If your
    > camera has a B&W mode, that would be helpful, but the image will still
    > require post processing.


    false.
     
    nospam, Sep 25, 2008
    #1
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  2. nospam

    nospam Guest

    In article <>, bino
    <> wrote:

    > >> The problem is that you won't see an IR picture per se, as the image
    > >> requires post processing to be anything but a dark red image. If your
    > >> camera has a B&W mode, that would be helpful, but the image will still
    > >> require post processing.

    > >
    > > false.

    >
    > You got some facts jackass? Experience? I've shot IR film and IR digital.
    > The red filter makes the color sensor see red. Period.


    except that the blue pixels also pass infrared light and depending on
    the camera, the white balance, the strength of the infrared filter and
    the raw processing, the results can be virtually anything.

    i've used a couple of digital cameras for infrared and modified one of
    them myself. none of them produce red images out of the camera. on
    the camera's lcd screen and the jpegs they produce, the result is b/w.


    if anything, there's a mild greenish cast, perhaps because the camera
    is boosting green due to the weak response of the green pixels with
    infrared light. the very same image when shot raw and processed via
    adobe camera raw has an entirely different appearance than with nikon
    or canon's software.

    saying that it will always be red is simply false.
     
    nospam, Sep 25, 2008
    #2
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  3. nospam

    Guest

    In rec.photo.digital bino <> wrote:
    | "nospam" <> wrote in message
    | news:250920081631382585%...
    |> In article <>, bino
    |> <> wrote:
    |>
    |>> The problem is that you won't see an IR picture per se, as the image
    |>> requires post processing to be anything but a dark red image. If your
    |>> camera has a B&W mode, that would be helpful, but the image will still
    |>> require post processing.
    |>
    |> false.
    |>
    |
    | You got some facts jackass? Experience? I've shot IR film and IR digital.
    | The red filter makes the color sensor see red. Period.

    Who said anything about a red filter ... in this thread?

    Actually, I would recommend a IR-passing filter (e.g. type 89) on the lens
    after the IR-blocking filter is removed. The sensor (with a replacement
    all-passing filter to keep the optics consistent) will pick up IR in other
    colors. This is because the color separation of the sensor is not designed
    to discriminate IR (and hence why an IR-blocking filter needs to be added
    in the normal case). The red channel will get the most IR. The blue channel
    will get a lot. The green channel will get some. And these will vary by
    what IR wavelength is involved. So you will get some false color effects.
    Directly viewing the image on the camera screen will give some funny reddish
    colors for sure. Post processing can then give you the effets you want if
    you were using the correct lens-front filter to begin with (type 29 for some
    effects, type 89 for others, and type 87 for yet others). In some cases the
    desired effect is achieved by making everything monochrome. In other cases
    the desired affect is a color product derived from adding or subtracting the
    various color channels. Additionally, multiple shooting of a stationary
    subject with different lens-front filters (the above plus 25, 23, 15, 12, and
    none at all) can give you multi-channel info to even be able to derive the
    original visual image unaffected by infrared (with the correct formula).

    --
    |WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
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    | Usenet from these places, find another Usenet provider ASAP. |
    | Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |
     
    , Sep 26, 2008
    #3
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