Archived posting to the Leica Users Group, 2000/05/18
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Takeshi Hashimoto wrote: > > > -- > > On Wed, 17 May 2000 19:15:36 Dennis Painter wrote: > >Looking through the viewfinder Peter Niessen wrote: > >> > >> Dear all, > >> > >> today I noticed that, when using the series VIII yellow filter on my 4.8/280 > >> Telyt, the infinity position had changed from infinity to a little > >> above the 100m on the distance scale. The filter itself is approx 4mm > >> thick. Is this result compatible with what others have observed? > >> > >> Cheers, Peter. > > > >Peter, > > > >I have pondered this off and on for a bit and cannot think of any way a > >perfectly flat piece of glass would shift the focus. I think some others > >mentioned that it will but don't think there was any real explanation of > >how. > > > >Not specifically addressed here: > > > >http://www.schneideroptics.com/white/long.htm > > > >But they basically claim no effect. > > It does by moving the focus back the equivalent of its thickness. > How does it do this? Does "moving the focus back" mean that it is as though the object 'seems closer' by the thickness of the glass? Would not be much effect for an object at infinity if that is the case. Again, how does it do this? Dennis