Archived posting to the Leica Users Group, 2010/09/04
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Thanks Henning. That led me to re-read about the construction of the B+W filters, which I use. I see that the lamination is not applicable to the UVs I have, as you say. They are made from Schott glass. I was mistakenly thinking of the Schott glass LCD protector that I have , which is laminated. I consider that Mark's contention that a filter will shatter into a million ultrasharp pieces and therefore be worse than no filter to be nonsense. I'm happy to use mine in any event and as I mentioned mine have prevented lens damage on three occasions. I don't understand why there are polarised opnions on this. Sorry, couldn't resist. I'm certainly not telling anyone else what they should do, only my personal preference and experience. Cheers Geoff http://www.pbase.com/hoppyman On 4 September 2010 16:52, Henning Wulff <henningw at archiphoto.com> 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. > > -- > > * 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 >