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InfraReD

Discussion in 'Photography Techniques' started by ReD, Dec 19, 2014.

  1. ReD

    ReD SC Hall of Famer

    Mar 27, 2013
    InfraReD

    Early Xmas present to myself I bought a 49mm step up adapter & a cheap Infrared filter 720
    Here are two early shots with fairly minimal processing – Silkypix doesn’t seem able to read the iR files well – it will either mean a lot more work or I have to find another process if I want to tweak the RGB values. These two images were done within my normal Picasa.

    I can see me getting a lot of fun out of this



     
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  2. ReD

    ReD SC Hall of Famer

    Mar 27, 2013
  3. Luke

    Luke Super Moderator

    Nov 11, 2011
    Milwaukee, WI USA
    Luke
    I know the filters available don't do true infrared, but they are close enough......there shouldn't really BE any RGB values, right? Or am I misunderstanding it?
     
  4. pdh

    pdh SC Legend

    Jan 2, 2011
    It's not so much the filters not being "true infrared" as the sensor not having much if any ir sensitivity.
    Cheap filters are likely to have a fairly shallow roll-off at the bottom end so they'll leak a bit towards orange.
    They will block almost all green and blue though.
    So what's mostly happening with putting a cheap ir filter on a non-ir modified sensor is just like putting a very deep red on.
    One thing I used to do on my sigma when I had it was to set the wb with the filter on. This gave quite a marked Wood effect.
    But whether it'll work with the x10's sensor I dunno.

    PL member lenshacker will be able to advise further and more accurately than I, though ...
     
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  5. ReD

    ReD SC Hall of Famer

    Mar 27, 2013
    you can still tweak - silkypix shows them all black & after playing they have a lot of grain
    maybe its my misunderstanding but I get more mileage from finepix studio & picassa but I have a lot to learn

    converting the infrared image in picassa with pseudo infrared converts them to all black
     
  6. usayit

    usayit SC Regular

    113
    Sep 4, 2010
    Yup. Every camera has different sensitivities to IR transmission. Camera that have a strong on sensor filter will only record the tiny bit of visible light that passes through the filter. This makes some cameras less-suitable for IR photography in their unmodified form.

    The Leica M8, for example, is well known to have "issues" with the IR spectrum. It was to the point that it was causing color issues on the final images (synthetic blacks went purple and skin color was on the pinkish side). The solution was to use IR cut filters on the front of the lenses. This issue can be used to the advantage for those shooting IR. WIth the M8 in bright sunlight, I can obtain hand holdable exposures. This is with the 720nm filter

    5910027161_f9d87a3c5c_b.

    This is with the Red and Blue channels swapped

    5929950484_4f3c31f2c8_b.

    Leica pretty much corrected the situation with the M9 with a stronger IR cut filter on sensor. So it pretty much makes the M9 near-useless in IR photography. I tried... I get almost a black frame with deep-red silhouettes. I would have to resort to long exposures in order to get a less-than-stellar image.

    If you really like infrared, the best solution is to convert a camera. I have an Olympus E-PL1 that I removed the on sensor filter stack resulting in a full-spectrum camera. It allows me to choose which filter to place in front of the lens. Shooting infrared with the full spectrum E-PL1 is pretty much like shooting with a regular camera.... you get normal exposures as you would expect in any given situation. This is with the 720nm.

    14611801538_19a01c3b4b_b.

    14786145536_4d869c23c9_b.

    The E-PL1 converted (DIY) cost me about $80. Instructions on Petapixel. Next step for me is to get my hands on a 820nm filter to further cut out visible and process in B&W.



    As for processing, I found that it makes it a whole lot easier if you set your camera's custom white balance with the selected filter on grass (or whatever is reflecting IR) prior to shooting. This makes a huge difference in processing afterwards. Also remember that bayer filter based sensors have twice as much green sensor sites than red or blue.... you are blocking a lot of green. At least for my E-PL1, I like to over expose just a tiny bit.
     
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  7. lenshacker

    lenshacker SC Regular

    192
    Nov 21, 2014
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  8. lenshacker

    lenshacker SC Regular

    192
    Nov 21, 2014
    Just a quick comparison that I used on Flickr to show how little IR that modern cameras let through, using a Wii lightbar. It uses super-bright IR LED's.

    Full-Spectrum modified EP2,

    15935127990_188d25ecf2_z. full_spectrum2

    Leica M8, about the same as a Nikon D1,

    15499927884_14f9acae33_z. M8_nocut

    Leica M9,

    16122245975_42266439cf_z. M9_1

    Olympus EPM1, unmodified,

    15934978228_c5abb00405_z. Oly_EPM1_unmodified

    Nikon Df

    15935052528_3e9c5c374f_z. NikonDF_Unmodified

    As modern digital cameras "have gotten better": an older camera or a modified camera is required for IR work.

    This is with the first Kodak DCS200ir, 1.6MPixel. 1993. It was expensive.

    16085241426_c632be3821_z. BEE1

    My next project is to try to get some pictures taken through this-

    15955059987_2eb8e4684f_z. Infrared Scope Type C-1

    Prototype IR Scope, 1940 type "C-1". After 75 years, still works.
     
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  9. usayit

    usayit SC Regular

    113
    Sep 4, 2010
    Just for more discussion....

    Two gels in front of my flash; primary blue and primary red. Pretty much blocks most of the visible spectrum except one can still see a little red if looking right at the flash. Taken with the same IR modified E-PL1 with 720nm filter @ ISO 400. Then converted to B&W using Silver-Efex applying a green filter and adjusting curves. Flash on camera, straight on....

    15536799324_ddf3748481_b.

    What's interesting is that the flash itself is not distracting to the subject because they can't actually see most of it. Yet... there is enough IR transmission that I was still able to bounce off my ceiling (10ft high) and still get enough exposure.
     
  10. lenshacker

    lenshacker SC Regular

    192
    Nov 21, 2014
    This is with a full-spectrum Coolpix 950 with a Magenta filter to remove Green light. The grass comes through in far-red and IR.

    15924240840_bf46b762df_z. ir_1 by fiftyonepointsix, on Flickr

    The closest that I've gotten to Infrared Ektachrome with a digital camera.
     
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