[Leica] WTB: IR/UV filters

[henningw at archiphoto.com (Henning Wulff)]

A lot of technical stuff I try to figure out on a logical basis, but 
that often fails me, or I ignore it :-). But usually, if I do ignore 
the logical conclusion, I try to figure that out as well. Leica usage 
falls into the latter category for the most part.

To UV filter or not to UV filter, I really don't care what others do. 
I think I got it figured out for myself, but that's just me.

On the other hand, when I see people walking around taking pictures 
over an extended period of time with the lenshood reversed on their 
zooms, that offends me. :-)




At 12:03 AM -0700 9/4/10, Richard Man wrote:
>What I don't really understand is why does anyone need to justify either
>decision to someone else and how someone's opinion or "100% of PROs"
>opinions should have any weight on anyone else. I am just glad that we still
>live in a (mostly) a free country :-)
>
>On Fri, Sep 3, 2010 at 11:52 PM, Henning Wulff <henningw at 
>archiphoto.com>wrote:
>
>>
>>
>>  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
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