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Thread: infrared film query..

  1. #1

    Join Date
    Nov 1999
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    Tacoma,WA
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    131

    infrared film query..

    i have a 4x5 monorail camera and am planning to use infrared for first time. my questions are:
    1. is 50- 100 rated iso normal?

    2. how many stops do you have to open up to compensate for the effect?

    3. how do you focus with large format camera? there are no marking for infrared on this camera.

  2. #2

    infrared film query..

    1. depends on the film (macophot?)
    2. huh?
    3. depends on how long the lens is, focus normally, then [from kodak]: try extending the lens by 0.25 percent of its focal length beyond the correct focus for visible light. That is assuming you are using a filter to block most of the visual light. Stopping down also helps.

  3. #3
    Multi-format, with beard.
    Join Date
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    Pasadena, CA
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    infrared film query..

    Hi Daniel,

    If you're using Maco 820, it is much like FP4 when no filter or a regular red
    filter is used in its behavior. If you want the full infrared effect, you need the opaque
    filter, and some trial and error. During the day, start with about ISO6 from a visible
    light reading - should get you in the ball park. Late afternoon or night don't have much
    infrared, so it will be more difficult to get the right exposures. If you have a way to
    measure infrared light, great - but a regular light meter won't do it. Maco
    is actually a rather nice regular film with no filter at all. It will pick up a little
    infrared effect with a deep red - a tad different than regular film - and the
    focus shift won't come in to play much if at all.

    I shoot Maco and have had good results during the day, with an opaque filter that
    gives black skies. As I've shot usually at somewhere between f22 and f45, focus
    has not been much of a problem - plenty sharp. I focus without the filter of course,
    and then go toward infinity with the image looking sharp instead of stoping my
    focus movement just as the image barely gets in focus. Seems to work fine. For
    close-up subjects, you'll have to see if somebody here has a more precise method.

    Make sure that the light traps are good in your holders, and limit the time they
    spend in direct sunlight if you can. So far though, using regular holders in nice
    condition, no issues.

    The URL for the Kodak tech sheet that suggests focus difference is:
    http://www.kodak.com/global/en/professional/support/techPubs/f13/f13.jhtml

  4. #4

    Join Date
    Nov 1999
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    Tacoma,WA
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    131

    infrared film query..

    sorry........here is more info on my lil dilema (haha)
    820 maco aura 4x5 b/w infrared, r72 filter and i live in washington state, keep that in mind....as it is a 50-50 crap shot on the weather....some days good some days...well, you get the picture.
    what i normally shoot is this.....parks-muncipal or nat'l/state parks. i usually work with b/w or slide film (velvia) when photographing any subject. hope this helps

  5. #5

    infrared film query..



    I don't adjust my focus for IR LF photography and haven't noticed a focus shift. With the variety of modern lenses, I don't think any simple rule could work. Here are two previous discussions:
    How do you adjust focus for infrared film? at http://largeformatphotography.info/l...ic/498338.html and focus shift with infrared film at http://www.largeformatphotography.in...ic/501706.html.


  6. #6
    Marco Annaratone's Avatar
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    infrared film query..

    The Maco 820 loses sensibility pretty fast above 820nm. I use an 89B filter that cuts below 650nm, and with a setting of 3ASA (three) I get good exposures under sunny conditions. (One should always add "typically" when statements about IR are made, it always depends on how much IR radiation there is in the scene, of course.) I develop it with Xtol 1+2, 14 minutes at 21C, 30 seconds initial agitation, then once every 30 seconds, long prewash to remove the anti-halo.

    In your case (R72) you are shooting within a somewhat narrower windows (720nm-820nm give or take) so you may have to decrease the relative ASA a bit more. It's always a bit of a trial and error but rating the film+filter combination at anything between 1ASA and 3ASA should give you negatives you can work with. And if the weather is overcast you probably do not want to shoot the Maco 820 anyway, I guess.

    I do not adjust focus. In my landscape shooting the depth of field takes care of any shift.

    Cheers

  7. #7

    Join Date
    Nov 2001
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    IL
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    infrared film query..

    You can shoot during overcast weather, just keep in mind that you will have to adjust your exposure and you may run into rather long exposure times with an IR filter. I shot some Maco film last November with an 88A filter (which is sensitive starting at around 750 nm). I metered as I usually do, then adjusted my readings for the filter factor, and wound up with 8 or 15 sec exposures with either f/16 or f/22 as the aperture. ISO on the meter was 6. Now it was an overcast day close to Thanksgiving and it was somewhat windy and late afternoon to boot. Here's a link to one of the the pics I took that day. I don't recall whether this is a silver print or a palladium print. There is detail in the tree trunk on the neg, but this print doesn't really show it. dianemaher.fotopic.net/p9564485.html

  8. #8

    Join Date
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    Tacoma,WA
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    infrared film query..

    hey diane,
    really like that shot!! makes me think of time i lived in oklahoma...has really beautiful winters. there was this tree (very similar to this one!!) by a small pond and it really luminated when about late october through mid november for some odd reason, but it reminded me of that. got anymore of that nature??

  9. #9

    Join Date
    Nov 2001
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    IL
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    infrared film query..

    No not really, Daniel. I needed to go out last year (and get away from my family) and I just happened to have IR loaded in my holders. I should try again though. Sadly, the tree in that picture no longer exists. It was quite rotten inside and fell back in January.

  10. #10

    Join Date
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    infrared film query..

    sad to hear that...what i really wish is that someone would publish a book for infrared, specifically for large format cameras...i mean the 35mm books are nice, but don't cover shift and swings,as well as the diferent filters and their affects on the film. as well adjustments need to compensate for filter affect as well some recommended exercises to help with using infrared. just a voacl thought....would anyone besides myself buy this book if it were to exist??

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