Archived posting to the Leica Users Group, 2006/12/21

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Subject: [Leica] Filter for the M8 B+W 486
From: eduardoalbesi at ciudad.com.ar (Eduardo Albesi)
Date: Thu Dec 21 21:30:46 2006
References: <00a401c72578$c8806770$6401a8c0@FrankDell2>

Don't you think an effective approach would be to provide a hot  
mirror layer on one of the optical surfaces *inside* the lenses, at a  
point where the light rays incidence angles are more parallel to the  
axis of the optical system and where internal reflections can be  
optimally minimized?

I think this would be an elegant solution if they can control, the  
internal reflections, as the lenses performance will not be altered  
neither on a digital nor on a film system. Leica should offer to  
incorporate such an internal coating on existing lenses at the time  
of the 6-bits conversion. At the same time, they should begin to  
market "digitally enhanced" lenses, with inner IR barrier coatings  
and 6-bits coding.

Best,

Ed


El 22/12/2006, a las 00:25, Frank Filippone escribi?:

> Hennning.... I agree that the angle of incidence will effect the  
> pass band..... but I am not sure how much..... and if it is within
> the specs of the filter tolerance itself....  I don't know.
>
> But we seem to agree that the filter mounted in front of the lens  
> has the same issues.....
>
>
> Frank Filippone
> red735i@earthlink.net
>
>
> A fairly small change in the angle of incidence can negate the effect
> of an interference filter. I don't want to do the calculation right
> now, but I wouldn't be surprised if the differences in the Leica M
> and DSLR incidence angles are enough to greatly influence the outcome.
>
> Hot filters in front of the lens would have a similar problem, though.
>
>
>
> _______________________________________________
> Leica Users Group.
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>



Replies: Reply from telyt at earthlink.net (Douglas Herr) ([Leica] Filter for the M8 B+W 486)
Reply from red735i at earthlink.net (Frank Filippone) ([Leica] Filter for the M8 B+W 486)
In reply to: Message from red735i at earthlink.net (Frank Filippone) ([Leica] Filter for the M8 B+W 486)