"leaking" Hoya filters

[Joshua_Putnam <josh@xxxxxxxxxxxx>]

If I remember correctly from looking at the transmission curves
of Hoya's infrared filters, even the really deep RM-90 and RM-100
are specified to transmit a small amount of visible red light, a
few percent of those wavelengths vs. almost all the light longer
than the cutoff wavelength.  The curves definitely look different
from those for B+W filters of the same cutoff points.

But there's also quite a difference among people in what they can
see through the filters right around the IR / visible boundary.
Some people consider an 89B or B+W 092 visually opaque, but I
have no trouble composing and focusing through an 092 on my OM-1.

-- 

 Josh@xxxxxxxxxxxx  is  Joshua Putnam / P.O. Box 13220 / Burton, WA 98013
                       "My other bike is a car."                   
                     http://www.wolfenet.com/~josh/
*
****
*******
******************************************************
*  To remove yourself from this list, send:          *
*         UNSUBSCRIBE INFRARED                       *
*       to                                           *
*         MAJORDOMO@xxxxx                            *
*----------------------------------------------------*
*   For the IR-FAQ, IR-Gallery and heaps of links:   *
*  http://www.a1.nl/phomepag/markerink/mainpage.htm  *
******************************************************