View Full Version : Center Filter 90mm 6.8

Spencer Ladd
7-Feb-2008, 21:03
Will the following work?

Rodenstock 90mm 6.8 with a Heliopan 67mm Center ND 3x Glass Filter

Peter K
8-Feb-2008, 01:21
Center filters are specially designed for a certain lens. So a wrong center filter doesn't works.

I haven't found any 3x ND filter on Helioplam's website. There is a ND 0.3 with 50% transmission and 2x extension factor and a ND 3.0 with 0.10% transmission and 1000x extension factor. Both filters are no center filters.

Bob Salomon
8-Feb-2008, 03:58
Yes it is essentially the same as the current Rodenstock center filter for the 90mm 6.8 and 75mm 4.5.

It will not work properly on the Apo Grandagon series.

Heliopan lists this as:

Neutral-Weitwinkel-Ausgleichsfilter in Spezial-Weitwinkel-Einschraubfassung
(Ausführung ND 0,45, Verlängerungsfaktor 3x LW–1,5)

Spencer Ladd
8-Feb-2008, 04:25
Thanks Peter and Bob.

I am going with Bob's advice. I can now go forward with my purchases.

Spencer Ladd