[Leica] WTB: IR/UV filters

[shino at panix.com (Rei Shinozuka)]

  it feels like years since the last filter kerfuffle.

as for myself, in 2007 i swapped heliopan UV-MRC Slims for leica UV-IRs 
and in 2009 i switched back.

-rei


On 09/04/2010 02:52 AM, Henning Wulff wrote:
> 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.
>