Infra-red film and M cameras?

[john_chan2]

Hey guys,

 

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Now I have a question regarding infra-red films and the M system. As many of you are aware the M lenses lack the IR focusing correction mark on them so you have to follow the general rule of thumb for this type of photography (F5.6 correction to the near hyperfocal range for wide-angle and normal focal lengths). Since I don't own any APO corrected lenses I was wondering if there is an easier way to do this? If I stop down to 5.6 or less then I don't really have to correct right (because hyperfocal range encompasses the correction point????). I was also thinking about going from Kodak graphs and just marking correction points on my lenses (with red nailpolish) if I can find the curves for my lenses. What do some of you suggest? (Assuming that you have experience with this type of film).

 

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Thanks in advance...

[j._o.]

I'm afraid your first solution is the one generally used by M

photographers. Stroebel in "View Camera Technique" talks of a

standard correction multiplied by the focal length, but that's

probably inaccurate for the much shorter focals used in 35mm

photography -- longer lenses require less correction for IR.

 

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As an M3 user I've never attempted IR, despite using a fair quantity

of EIR in the past in other cameras.

[john_collier]

Here is a message from the Leica-users archives from an

experienced IR user (Henning J. Wulff):

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I shoot IR film quite often in my M4, and it is quite easy. I don't

usually shoot wide open, but if necessary, I'll still do it. With

newer lenses I set the focus point approximately at the closer f/2

depth of field mark, with older (70's) lenses I set it at about the f/4

mark. This is all with the Kodak HIE film, which has sensitivity

further into the IR than other readily available films. With others

(Konica 750, the E-6 film and the Ilford film) I don't do any

adjustment at all. Especially the more recent lenses are so well

corrected, and the IR sensitivity is so limited, that refocussing

rarely brings any benefits.

 

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The shutter has no light leak problems.

 

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For the Kodak HIE film I have a Leica 39mm IR filter, which is

equivalent to an 89B, and otherwise I use gels cut to size behind

a UV filter; mostly 89B or 87. The 25 filter doesn't do quite

enough with the HIE.

 

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The main problem with IR is that you have to bracket a lot, and

the film is expensive, but if you are going to use it, Leica-M's are

ideal.

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Cheers