Archived posting to the Leica Users Group, 2000/05/14

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Subject: [Leica] Re: Long lens and filter question
From: Jim Brick <jim@brick.org>
Date: Sun, 14 May 2000 11:05:30 -0700
References: <Pine.HPX.4.21.0005141219520.288-100000@hpbai1.ifh.de>

Filters and telephoto lenses are not a marriage made in heaven. As you
know, a filter on any lens will slightly degrade the image. Just more so
with a telephoto. The APO 180/3.4 R lens will simply not work with many
filter brands. I have read this numerous places and know it from "personal"
experience. It is my understanding that filters on a telephoto MUST be
absolutely aligned with respect to the optical axis and that the glass
surfaces must be precisely flat and parallel. This means expensive filter,
such as B+W or Heliopan. This is possibly why, other than the size factor,
many telephotos have filter slots within the lens.

Even in the expensive brand filters, there are samples that do not meet the
criteria for use on some telephotos.

IMHO,

Jim


At 08:50 AM 5/14/00 -0600, John Collier wrote:
>I have little personal experience with this but have read of it several
>times. Dick Gilcreast mentioned this effect in his excellent LHSA Viewfinder
>article on the 135/4.5 Hektor.
>
>> From: Peter Niessen <niessen@ifh.de>
>> 
>> today I noticed that, when using the series VIII yellow filter on my
4.8/280
>> Telyt, the infinity position had changed from infinity to a little
>> above the 100m on the distance scale. The filter itself is approx 4mm
>> thick. Is this result compatible with what others have observed?
> 

In reply to: Message from Peter Niessen <niessen@ifh.de> ([Leica] Long lens and filter question)