[Leica] Ir filter and film cameras, take it off

[henningw at archiphoto.com (Henning Wulff)]

At 4:02 PM -0700 3/18/07, Frank Filippone wrote:
>Can you be more specific?  What particular brand of which filter #?
>
>According to the filter specs. Most film should not be affected..... 
>notice the words ... most and should......
>
>I will compare specs of film spectral density and filter pass band......
>
>Fancy words for taking another look at how the 2 should work together......
>
>Frank Filippone
>red735i@earthlink.net
>

Frank, all the IR hot filters that work by means of interference 
coatings will do that. Once the incidence angle is too great, the 
frequency shift causes the colour shifts. No help for it.

Transmission subtraction filters ('dyed' or 'sandwiched') filter 
don't do that hardly at all, but the cutoff frequency for IR 
suppression isn't nearly as steep, so aren't that useful in general.

So. Take off the IR hot filter when shooting film, or deal with the 
same cyan drift in the corners with WA lenses as the digital shooters 
do; ie, scan the film and then correct the radial luminance errors in 
the correct frequency. No good for slide shows though.



>a word of caution to remove the ir filter when shooting color
>film/silde. just got a roll back and i have cyan colors on the
>corners. shot with zeiss 21/ir filter, fuji provia and m6.
>
>--
>   -------------------------------------
>   regards, mehrdad

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