Focusing Leica lenses with infrared film

Discussion in 'Rangefinder Forum' started by tbm, Aug 8, 2005.

  1. tbm

    tbm Member

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    I would truly like to finally shoot some b&w infrared film with my Leica M and R lenses, but none of them have a marking for focusing. Does anybody have a foolproof method for accurately focusing said lenses?

    Terry
     
  2. Ole

    Ole Moderator Staff Member

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    It would all depend on the lens. There are unfortunately no absolute rules for how much to shift focus with IR film.

    However: Unless you use Kodak HIE it doesn't matter. All other films are only sensitive to near-infrared down to about 800nm, which is close enough to visible light that most lenses will be fairly wll corrected. I've shot the new MACO IR 820/400 with a Voigländer 21mm lens, nd everything was tack sharp. Of course the extreme DOF with a 21mm lens helped a lot :smile:
     
  3. mono

    mono Subscriber

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    As far as I know Leica lenses need no correction with IR! That is why you`ll find no IR marks on them.
     
  4. Claire Senft

    Claire Senft Member

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    I have no experience with infra-red film...zero. I am thinking about Ole,s remark inre: the 21mm Voigtlander. He states that the exreme depth of field helped a lot.

    I wonder if this is so. If the focus shift happens at the film plane..depth of focus..then the shorter the focal length the more of a problem you would have. Stopping down of course would help.
     
  5. Woolliscroft

    Woolliscroft Member

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    Stop down a bit and the DOF should get you through. It works for me.

    David.
     
  6. Ole

    Ole Moderator Staff Member

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    Since I used a Bessa-L (no rangefinder), all my distances were guesstimated. So DoF was a really great help!

    Any difference in focal plane between IR and visible light should be less than the thickness of the emulsion from what I have seen of data on the 21mm Color-Skopar.
     
  7. JohnArs

    JohnArs Subscriber

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    Mono is right on!
    The quality of Leica lenses is up to the IR span and so they need no correction.
    So don't worry be happy!
     
  8. Lee Shively

    Lee Shively Member

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    I've had limited experience with IR films but the biggest obstacle was using the dark red filters, not the focus compensation. Stop down a bit and you won't have any problems. Leicas--all rangefinders--overcome the problems of using dark filters since you don't have to focus through the lens.
     
  9. Helen B

    Helen B Member

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    I'm not so sure that Leica lenses are corrected into the infrared. Remember that an IR focus mark only applies to one wavelength, probably at one distance setting. With IR film you have a choice of filter and film combinations that result in different centre wavelengths. If you are focussing by eye, rather than by scale, through a red filter then the focus point may already be affected by wavelength.

    I have read sources on the internet (Willem-Jan Markerink is one) that say that Leica do not put IR marks on their lenses nowadays because they could give a false sense of accuracy. Whether that is true or not, I share the view that the answer is to stop down.

    Best,
    Helen
     
  10. Trivette

    Trivette Member

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    I'm not sure either. The 40mm Minolta M-Rokkor has a focussing mark for IR, and it is optically identical to the 40mm Summicron-C.
     
  11. Dr.Kollig

    Dr.Kollig Member

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    Had a look thru my Leica lenses, could not find a single one with IR-mark, not even 1936 90/4 seems to have one, also none on my 1950 Carl Zeiss Jena, modern Zeiss have the IR-mark at scale of depth position "aperture 4". My Nikon 105/2.5 SM says 5.6 my 50/1.2 F also says 5.6. So my idea is as long as the lens is not a APO type, I would focus my rangefinder and then adjust this distance to scale of depth aperture 4 or 5.6 -IF using Kodak High Speed Infrared.
    For films like SFX 200, APX 200 S which are only sensitive to 750 nm and can be used with 25/29 filters I would just leave it as it is.
    Only Kodak High Speed Infrared combined with a Wratten 87 or B&W 92 should require a focus correction. Say object is close to infinity try hyperfocal distance...
    In doubt one picture without correction one with correction...

    Kindest regards,

    Wolfram

    post scriptum: the quality of a lens is not directly related to its price.
     
  12. Trivette

    Trivette Member

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    Thanks for the information, Wolfram. On my 40mm Minolta lens (a multi-coated version of the 40mm Leitz Summicron), the IR mark is about halfway between f/4 and f/5.6 on the DOF scale.

    Richard
     
  13. Claire Senft

    Claire Senft Member

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    One should not assume that an APO lens is corrected into the IR region. It may be but a full apo correction does not require bringing IR to the same focus as visible light.

    The only lenses that I can think of at the moment that a fully corrected for IR are the Zeiss Super Achromats and a Hasselblad lens is of little use to a 35mm rangefinder camera.
     
  14. kaiyen

    kaiyen Member

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    Another tidbit - if you do have to use a wider aperture for some reason, if you're using a red 25 filter you should still have more than enough visible light for the resulting image to look sharp and in focus. I have shot images at f4 and f5.6 and they still look fine.

    allan
     
  15. Ole

    Ole Moderator Staff Member

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    My LF negatives with Lee IR filter, MACO 820c and a Zeiss Planar 135mm at f:3.5 were sharpest without any correction. I tried both no correction and advancing 1.5mm. Same with a 210mm Xenar at f:4.5 and a 360mm Tele-Xenar at f:5.5. These lenses should be different enough to be representative of a large number of fairly simple lenses.
     
  16. tbm

    tbm Member

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    I exposed a roll of Kodak HIE infrared film yesterday with an EI of 320 in my backyard, including palm trees, 12-foot-high wax leaf hedges, my swimming pool, and other plants in various shots. Instead of my M6, I used my R8 and 35mm Summicron. I used zone focusing, setting the infinity mark on f/8 on the right, resulting in everything from 7 feet to infinity showing up sharp on the negatives. I developed the film in Diafine for 5 minutes in both A and B solutions. Examination of the negatives with both 4x and 8x loupes shows acceptable tonality and contrast, which I will have to tweak via the dials on my Saunders dichroic enlarger.

    I plan to expose another roll with my R8 and 35mm Summicron by setting the film speen at 250 and developing it in D76, simply to observe the differences in grain, tonality, and contrast and determine which developer and EI I will permanently prefer. If neither leave me completely pleased, I might be inclined to process it in Xtol.
     
  17. tbm

    tbm Member

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    Attached are scans of two of the negatives I exposed with my Leica R8, 35mm Summicron, and Kodak's HIE infrared film in my backyard, using the hyperfocal setting I mentioned in the preceding message. They came out fine in Diafine with noticeable grain. I'm next going to reduce the speed setting on my camera from 320 to either 250 or 50 and develop a second roll in D76 for further testing.

    Terry
     
    Last edited by a moderator: Aug 21, 2007
  18. danielclift

    danielclift Member

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    One thing you might want to check before embarking on a shoot is whether your shutter is opaque to IR. I've never tried using an M for shooting IR photos, but I recall reading a long time ago (I have no idea where) that some cloth shutters allow enough IR through to cause fogging. It might mean that you need to keep the lens covered except when you take a picture.
     
  19. lulalake

    lulalake Member

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    Terry,

    Actually there is a hard and fast rule. IR focal length is about 1/500th of a given FL longer than visible light, therefore in a 50mm lens the lens must travel 0.1mm farther away from the film plane for the sharpest focus. In an 85mm lens its 0.17mm etc., etc.

    The name on the lens has nothing to do with it, it’s the properties of light and glass here that count, Leica, Mamiya, Canon, Nikon et al.

    How this applies is in determining how much to twist the lens to achieve the extra 0.1 length.

    Cheers

    Jules

    http://groups.yahoo.com/group/Infrared_Photography
     
  20. colrehogan

    colrehogan Member

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    I know of several people besides myself who have used am M for IR photography. There should be no problems at least with the M6.
     
  21. Fotohuis

    Fotohuis Restricted Access

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    While testing the new Rollei Infrared-400 film (820nm) I made the corrections of my Canon lenses with the IR mark. Corrected for 800 nm, but also depends on the filter you are using (in my case Heliopan 715 nm).

    Because I bought a Leica M7 several month's ago I also would try this film in the M7. So I called Leica - Solms Germany (I am the owner of the Summicron 2,0/50mm and the Elmarit 2,8/28mm) if they could explain how to correct.

    Their APO lenses are corrected wide in I.R. so there you don't need correction and for my Elmarit 2,8/28mm the DOF is enough to prevent any problem for this film.
    The Summicron (50mm) you can correct from infinity to 50m. Regular Leica (M) lenses do not have any correction mark. So far the remarks about this item from one of their product specialists in Solms, Germany.

    Best regards,

    Robert