Archived posting to the Leica Users Group, 2000/07/25

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Subject: RE: [Leica] Leica or B+W Filters
From: "Bergman, Mark A." <mabergm@nppd.com>
Date: Tue, 25 Jul 2000 09:18:22 -0500

My understanding of multicoalting is that it improves light transmission
through multi-layers of glass.  Since filters are usually one piece of glass
I wouldn't expect any coating to do much of anything.

Having used Leica rangefinders for over 20 years I have used (and collected)
a huge assortment of filters.  Waltz, Hoya, Leitz, B&W, etc.  I have never
noticed a difference using any of them in my slides.  A few years ago
(filters are a never ending topic) I tried various brands color contrast and
UV filters on my 50 Summicron with Kodachrome.  Same landscape picture same
roll.  No difference that I could detect.  Coating filters, and now
multi-coating, is a fairly new development.  IMHO I think it is mostly
marketing hype.

- -----Original Message-----
From: Bob Walkden [mailto:bobwalkden@hotmail.com]
Sent: Tuesday, July 25, 2000 9:34 AM
To: leica-users@mejac.palo-alto.ca.us
Subject: RE: [Leica] Leica or B+W Filters


Hi,

I am now equally curious, since you've asked this question twice of 
different people.

Do you think that standard coated filters are the equal of (or perhaps even 
better than) multicoated filters?

If so what tests have you done, or what pointers do you have to others' 
tests?

Some of the filter manufacturers, such as B+W 
(http://www.schneideroptics.com/filters/filters.htm) make quite specific 
numerical claims about the effects of their filter coatings and the 
difference between double- and multi-coating is documented. Of course 
whether this is noticeable by ordinary humans under ordinary conditions is a

different matter, but the numbers are there and open to challenge if you 
think you know differently.

Cheers,

Bob


>From: Austin Franklin <austin@darkroom.com>
>
>I am curious what you base this claim on for a filter.  Have you done tests
>your self, or do you have pointers to test that others have done that show
>the image degraded by, say a single (actually double, one each side) coated
>filter, such as Heliopan 'standard' coated filter vs any of the 'other'
>multi-coated filters?  Or is this just hear-say and speculation?
>

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