Infrared 101?

Discussion in 'B&W: Film, Paper, Chemistry' started by yeknom02, May 22, 2012.

  1. yeknom02

    yeknom02 Member

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    Here's what I have:

    IR Filter: B+W "092" filter (89B/R72).
    Film: Efke IR 820 Aura (2 rolls), Konica 750nm (1 roll).
    Camera: either Nikon FE2 or Konica Auto S2.
    Meter: either the camera's internal meter (covered by the IR filter) or a Gossen Luna-Pro F.

    If I want to keep bracketing to a minimum (hey, film is expensive), then how should I go about shooting with this setup?
     
  2. HowardDvorin

    HowardDvorin Member

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    The meters in your cameras do not see infrared light. The amount of infrared light varies. So it is best to bracket.

    Sorry, I don't have a better answer

    Howard Dvorin
     
  3. Brian C. Miller

    Brian C. Miller Member

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    You will get an EI of something like 3, 6, or 12. You will have to bracket a bit to find out what your development times will be based on how you want the film to develop. But after you establish your own EI you probably won't loose too many shots if you don't bracket.
     
  4. Maris

    Maris Member

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    The ratio of infrared to visible light is variable so the E.I. you set on your visible-light meter can vary too.

    I haven't shot Efke IR820 behind a IR720 filter in the 35mm format but have exposed maybe a hundred rolls of 120 and maybe a hundred sheets of 4x5 and 8x10. Connecting what I saw, what I did, and what I got, the E.I. values that work for me are:

    Front-lit sunny day subjects: E.I. = 1.5
    Back-lit sunny day subjects: E.I. = 1.0
    Open shade: E.I. = 1.0
    Overcast, stormy, dramatic: E.I. = 0.5 maybe 0.25

    The good thing about infrared is that there is no blame if you didn't get what you expected. You can't previsualise what you can't see. Something weird/wonderful usually turns up.
     
  5. wildbill

    wildbill Member

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    two very different films.
    1/4@16 for the konica in full sun, just trust me I've shot tons of it with that filter
    1 sec @16 for the efke.
    google the shit out of it.
     
  6. Alex Muir

    Alex Muir Member

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    Hi. I have had good results using the Efke IR 820 film. I used the same Gossen meter as you have set to 4.5ASA. I originally bracketed one stop above and below 6ASA which meant that I got 12 shots to a roll. From this I concluded that 4.5ASA worked best. The camera used was a Nikon FE. The filter was the Hoya R72 and my general technique was to use incident readings. I would, however, recommend bracketing as others seem to use a lower speed for this film. I would also advise you to wait until there is plenty of sunshine as you are more likely to get usable negatives when there is plenty of IR around.
     
  7. paul_c5x4

    paul_c5x4 Subscriber

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    If you are bracketing, I'd suggest 1.5 to 2 stops either side rather than just one stop. Just processed a few sheets of IR820 that I had shot with a one stop difference and there is very little change in density.
     
  8. wildbill

    wildbill Member

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    correct indeed.
    that's why I always say bracketing is for sissies. I use a light meter instead. HA!
     
  9. Roger Cole

    Roger Cole Member

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    For infrared? You have a meter that reads infrared? Or was that a joke?
     
  10. Newt_on_Swings

    Newt_on_Swings Member

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    Semi hijacking this thread.

    I got a b+w 099 filter coming in. It's orange in color. I have used orange filters and do routinely.

    There are no posted filter factors for this filter at all. Anyone happen to know?

    Id like to use it with regular panchromatic films (im guessing it will work just like an orange filter) as well as HIE.

    Filter factors or ei ballpark would be nice, I'd rather not burn precious film bracketing or shooting an entire roll for tests.
     
  11. scheimfluger_77

    scheimfluger_77 Subscriber

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    Newt, I have one of these filters and it is a medium-light orange, factor appears to about 2/3 of a stop with my initial tests. I bought it for use with IR film and get minimal results alone, however combined with a #29 dark red it begins to produce some good ir effect.

    As to previous comments about light meters not reading IR, I don't think that's true. A 720nm filter placed over the sensor on my Luna Pro meters give readings within about 3 stops of unfiltered readings, so i expect that like digital sensors there is some IR sensitivity. At least that's been my experience.
     
  12. DWThomas

    DWThomas Subscriber

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    I suspect you're correct and I also suspect it may vary a lot between different types of meters. The latest generation of IR films have such limited bandwidth that they are almost looking at visible wavelengths anyway.

    As far as I know, most "alternate technology" cameras have IR attenuation filters on the sensors because the basic sensor has high IR sensitivity. I would expect to see different characteristics between selenium, CdS and silicon cell meters too. But in my opinion, there are so many variables working with IR -- first and foremost, we can't see it, so the "usual" intuitive adjustments are unavailable, and the amount of IR varies by season and time of day -- I don't see how a bit of testing and bracketing (at least in the first couple of passes) can be avoided. The suggestion of taking one shot unfiltered, on at least the first roll, to verify the basic workflow is also a worthy use of one frame!
     
  13. Newt_on_Swings

    Newt_on_Swings Member

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    Indeed I realized that I pretty much have to try a few tests esp with the tip of stacking two ir filters. I have a spot meter and I'll also test that as well with the filter over that and report my results, mine is from Polaris. I just need some sun here!
     
  14. Rich Ullsmith

    Rich Ullsmith Subscriber

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    If it is of any help. I just finished five rolls of the Konica 750. I rated it at EI3 with the 89b filter, and bracketed one below and above. D76 1+1 at 70 for 11m.

    I have not contacted everything yet, but generally the frames with additional exposure were closer to the mark. Of course everything has to do with the quality of the light, but it appears that EI3 is a good starting point. You will get workable negatives.

    I do not know about the other films you mentioned.
     
  15. Roger Cole

    Roger Cole Member

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    Yes, you are right of course. I should have said that they are not calibrated for infrared.

    This could probably be done however, if someone were so inclined, so that you could read through an optically opaque IR filter and get a useful reading.
     
  16. Craig Swensson

    Craig Swensson Member

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    How does the filter type chosen effect the exposure with Efke 820? I have an 850nm filter, should i be using 720? I did get some good results with this filter, just checked the details and the best were 1sec @ f16, though other shots at same exposure were not as good.All were shot within 4 hours on the same day but at different locations and aspects.
     
  17. cmo

    cmo Member

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    We had a loooong thread about IR film exposure before.

    I recommend to soup it in XTol 1:1 or Diafine to get a little more than 3 ASA. XTol results show less grain than Diafine results with this film.

    Then it all comes down to use 6 or 12 ASA with the Efke. Meter without the filter. If your lightmeter does not allow 3, 6 or 12 ASA just set it to 100 ASA and add 4 stops (12 ASA), 5 stops (6 ASA) or 6 stops (3 ASA).

    Other recommendations:

    - Photograph on bright sunny days. IR photography is possible on dull days, too, but results have a tendency to be, well, dull.
    - Motifs in front light might look boring, sidelight and backlighting render more interesting results.
     
  18. DWThomas

    DWThomas Subscriber

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    Based on my limited experience, the 850nm filter should be OK with the EFKE film - you might need one stop more exposure for the 850 than the 720. If you run the cutoff that high with the Rollei material, you'll be looking at another 5 or 6 stops over the exposure with a 720.
     
  19. mrred

    mrred Subscriber

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    Points to consider....

    1) Look for a couple of rolls of SFX (ILFORD) in your local store. It works well and will be likely sold where ever they sell ilford films. If you order online, go get the real stuff. The first one to experiment, and the second to do it right.

    2) Choose a lens that has a red dot, just left of the focus line on your lens. This will be your IR offset for this lens. These marks were provided years ago, not so much now. Look at your older lens.

    3) You develop your film at box speed. IE: SFX gets developed at 200 iso. The EFKE at it's box speed. Exposure (EI) is to compensate for the massive (usually -4 stops) light loss of the filter. So....IS0 200 - 4 stops is EI 12. Take one shot on the roll with out your IR filter. When you develop, that will be your reference image for proper development. IR film witll still develop as any pan film.

    4) Try to load your film in as much darkness as possible. This stuff is more sensitive than other films.

    5) Keep it fresh. IR sensitivity drops fast with age. It will turn into normal pan film, and can be shot that way when it gets old.

    6) Best time of day are opposite. High noon is awsome. You want heat from the sun, winter or summer.

    So what I do.....

    1) Find a scene.

    2) Meter for the box speed of your film. If using the one in your camera, take the filter off your lens to do this.

    3) Put your camera in manual mode and take the reading from above and adjust for -4 (or -5) stops. If this is the first time you have used your filter, try both.

    4) Focus without the IR filter. If you have a marked lens, adjust accordingly. If not, you will need to braket to find where your sweet spot is. Take notes.

    5) Put the filter on and shoot.

    You should try to stop down as much as possible until you have worked out the focus on your lens. Develop with the developer you are used to. You do not want to introduce too many variables until you get the basics worked out.

    Have fun!
     
  20. Newt_on_Swings

    Newt_on_Swings Member

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    I got my B+W 099 filter in today, just a bit before. It is a light orange, darker yellow color filter. First thing I did was test it with my spot meter, with it over the lens, and off. Its only about ~2/3 stop. I suspect it will act exactly like a orange filter on both Pan and IR films lol. The literature indicated its supposed to be used with color IR films. I will try some film with it this weekend. The same seller had the 092 which I totally didnt see which sold for really cheap too. Kinda kicking myself for that one, Alas I will keep using a cheapo 720nm IR filter I have.
     
  21. scheimfluger_77

    scheimfluger_77 Subscriber

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    This is curious. Strictly speaking you shouldn't be getting any exposure with an 850nm filter if a film's sensitivity cuts off at 820nm.

    In my recent tests I've been working with Rollie IR400 and 80s. I get a speed of about 1 with the cheap 720nm filter I'm using in both films using a C330 and pinhole cameras. Recently I used a 760nm filter on the IR400 and got some pretty stunning results. The asa setting on my Luna Pro? -5 See if you can figure that one out. ;-) I always try to express my exposure needs in terms of the speed setting on the meter, that way I don't have to jockey filter factors in an exposure calculation.
     
  22. DWThomas

    DWThomas Subscriber

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    Whoops! That's what I get for working too fast. I was seeing 850 in the question but my scrambled brain was thinking 750. It was a 760 nm I used with only minor difference on the EFKE material. I wish I could go back and edit that post, but we've passed the time window. (Hate it when that happens!)

    The Rollei IR400 makes some statement that it "extends to 820 nm" but the curve I've seen looks as though it's already starting to drop at 700 or so, which accounts for having to use much larger corrections with a 760 filter on it. I believe the EFKE goes to the high 700s before it starts to drop. Finding curves and detailed units seems a bit challenging on these films. And I can't say I have seen a definition of "cut-off." It looks to me as though the nominal numbers are some degree of reduced sensitivity, but you might still get something through beyond the nominal "cutoff" at the cost of considerable additional exposure.

    So practically speaking, you're correct. Anyway, thanks for catching me at that, apologies for the misleading jabber.

    (Alas, Kodak HIE went out to the 900s!)
     
  23. cmo

    cmo Member

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    Inimitable marketing BS, a unique selling point for Maco stuff :whistling:

    And that applies to filters, too. If some chinese manufacturer puts "900" on a filter that only means there is a "900" on a filter unless you use a filter from a premium manufacturer, then it will have a pretty sharp cutoff at 900nm. The el-cheapos might be labeled "sort of IR", but they work fine. I used a Cokin IR filter - acrylic stuff - for two years until it was so scratched I replaced it with a good glass filter. It's better, but not by a huge amount.