Leica infrared filter information

[Joe S]

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I have a Leica chrome 39mm infrared filter labeled IR.   It appears to take around 7 stops.   Would this be a 720nm filter?    I would like to use it with Rollei  IR400 infrared film and would like to know its suitability.

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[giannis]

11 hours ago, Joe S said:

labeled IR.   It appears to take around 7 stops.   Would this be a 720nm filter?

Sounds exactly like what a 720nm filter would do.

Realistically the only current films that have decent response/speed at that part of the spectrum are Rollei 400IR, Adox HR-50 (and the same emulsion based Rollei Retro 80S) and Rollei Retro 400S.

 

[Pyrogallol]

I have used the “IR” Leitz filters, along with other red filters ranging from an ordinary 25A up to the ones like the “IR” which you can hardly see through. With all of them I give +5 stops using Rollei 400 Infrared film. Using a hand held meter, not through the lens metering.

Edited February 20, 2022 by Pyrogallol

[Bobitybob]

When I started using IR film I did a bit of 'googling' and the following is a short list of the available info I found,

1. Use a rangefinder camera, as you will not be able to see anything through the filter if you use a SLR.  If you only have and SLR then remove the filter set your focus and adjust for IR and replace the filter,
2. Use a camera without a film window in the door if possible, if not cover the window with black tape,
3. Loading the film in low light is preferable and complete darkness if possible.  Avoid direct light,
4. Use a 720nm filter for maximum IR effect, but can be used without a filter as a normal B&W film with very slight IR effect,
5. If using a camera with TTL metering, leave the camera ISO set to film box speed, with our without a filter,
6. If using a an external light meter, or a camera with a non-TTL meter, set to ISO 12 or as near as possible (25 or 50, bracket exposures if the image is important).  Set camera shutter speed and aperture based on the light meter readings,
7. As IR light focuses slightly differently to visible light use the IR focus marks on the lens if available, and as narrow an aperture as possible,
8. USE A TRIPOD.

For the best results from infrared you should aim to include some foliage to give the trademark white glow. You don’t always need bright sunlight, in fact a cloudy or overcast day can also achieve good results.  Shooting in the summer provides more greenery and ensures there’s plenty of chlorophyll in the leaves (glows in IR light). Try to contrast your greenery with something else such as rocks, buildings, stonework or try some water and sky for darker colours.

Edited February 20, 2022 by Bobitybob

[Joe S]

Thanks for all the feedback.    Sounds like I should be close with some bracketing.

[Pyrogallol]

Agree with what has just been said. Classic period Leica lenses have an “R” focussing index for infrared use.

yes, bracket a bit as meters are not calibrated for infrared light and there may be more or less than you think.

Infrared film using time is coming up, in the northern hemisphere. The spring time produces the best results in foliage.