[Leica] M8 magenta problems - Leica offer a solution

[henningw at archiphoto.com (Henning Wulff)]

>That implies there is a different code of each specific lens design 
>( DR Summicron, Rigid Summicron, next version, last version,
>etc.)..... different absorption characteristics....
>
>We need to find out more about the lens coding... Which codes for 
>which lenses.....
>
>Didn't someone offer to compile this list?
>
>Frank Filippone
>red735i@earthlink.net
>
>My guess is that every lens absorbs some amount of IR, and that the 
>lens coding will tell the firmware how much IR made it through
>the lens.

Lenses don't absorb much IR until you get approach the thermal 
regions. Anything useable for IR photography gets through pretty much 
any lens. If you use an IR cutoff filter like Leica proposes, lens 
coding shouldn't make a lot of difference.

The images which showed high IR reflectance under incandescent 
lighting at ISO 2500 were taken with a couple of different lenses, 
and all showed the same effect. I would try the cutoff filter without 
lens coding first to see if the results were OK.

I'm still not convinced the coding is worth the trouble for anything 
except EXIF data.

-- 
    *            Henning J. Wulff
   /|\      Wulff Photography & Design
  /###\   mailto:henningw@archiphoto.com
  |[ ]|     http://www.archiphoto.com