[Leica] WTB: IR/UV filters

[mark at rabinergroup.com (Mark Rabiner)]

Henning I'm with you on all your arguments that I can see laid out below.
especially a lens shade being far better projection than a filter and a
filter being used only for good purpose. I feel "every day protection"
(prophylactic?) not being one of them.
It was my impression that the filters coming out of the Tiffin company had a
long and continued commitment to the lamination process. They were proud of
NASA being one of their returning clients. I avoid Tiffin only as a last
result because the lamination process struck me as inferior to dyed glass.
It seemed like a gross compromise. Sticking what appears to be a gel in
between two filters. 6 surfaces total. But I'm guessing they are still doing
it with all not just their polarizers.

Not taking seriously the example of the top people in a profession is just
not plain odd. But idiosyncratically arrogant.

--------------------
Mark William Rabiner
Photography
mark at rabinergroup.com


> From: "Henning J. Wulff" <henningw at archiphoto.com>
> Reply-To: Leica Users Group <lug at leica-users.org>
> Date: Fri, 3 Sep 2010 23:52:53 -0700
> To: Leica Users Group <lug at leica-users.org>
> Subject: Re: [Leica] WTB: IR/UV filters
> 
> At 9:45 AM +1000 9/4/10, Geoff Hopkinson wrote:
> 
>> Why do you think that the filters would likely shatter into a million 
>> ultra
>> sharp pieces? Good ones at least are laminated materials.
>> 
> 
> At present only polarizers are still sometimes laminated; most others
> are dyed in the mass. The latter would shatter.
> 
> In earlier times coloured filters were laminated because the dyes
> could be controlled better in gel form than as dyes added to molten
> glass. They were abandoned when dyed in the mass became possible
> because the gels tended to fade relatively quickly, and they
> necessitated thicker filters which caused a lot of plano-parallelism
> problems. I once (in the 70's) checked about 50 filters; over 75% of
> the laminated gel types had surfaces that weren't perfectly parallel
> which would cause serious problems with some lenses. The gels also
> didn't really provide any structural strength; not like the vinyl in
> laminated safety glass.
> 
> As far as the UV filter argument goes, the filter ring ding vs. lens
> rim ding I can understand, but my lens shades do an even better job
> and they shade besides. Also, if you shatter the filter after
> whacking the lens against something, it does not necessarily follow
> that the front element would have been damaged if the filter had not
> been there. Maybe yes, maybe no.
> 
> As you might guess from the above, I use filters when there is a good
> reason, but leave it off otherwise. I did some tests once which
> showed that under some circumstances the images gets slightly
> degraded when a filter is used. Not often, but still...
> 
> If you use a filter, make sure the coatings are good. It doesn't have
> to be the most expensive one.
> 
> -- 
> 
>     *            Henning J. Wulff
>    /|\      Wulff Photography & Design
>   /###\   mailto:henningw at archiphoto.com
>   |[ ]|     http://www.archiphoto.com
> 
> _______________________________________________
> Leica Users Group.
> See http://leica-users.org/mailman/listinfo/lug for more information