P. J. Alling <webstertwenty...@gmail.com> wrote: > The problem you're having Dave is that the Hoya R71 isn't an exact equal > to the Wratten #87 filter. It allows enough Red through to over power > the Red channel which will cause less crisp images.
Exactly. The R71 is more like an 89C which looks like a strong red filter and is still somewhat transparent for the human eye. The 87 is totally opaque. The Wratten #87 has the additional advantage of being available as a gelatin filter and is thus less expensive than e.g. a Hoya R71. I'm using it in a Cokin A filter holder. This way, it's also far easier to mount and remove for checking the framing than a threaded glass filter which would have to be screwed in and out all the time. Ralf -- Ralf R. Radermacher - DL9KCG - Köln/Cologne, Germany Blog : http://the-real-fotoralf.blogspot.com Audio : http://aporee.org/maps/projects/fotoralf Web : http://www.fotoralf.de -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
