This updates my efforts to get the best B&W digital image capture (all things considered and for my preferences, of course). I continue to believe the extended red sensitivity offered by the astro-photography cover glass conversion, which replicates the old Tech Pan spectral sensitivity, results in a superior B&W camera.
(My original post on the original astro cover glass was on June 11, 2016, at https://groups.yahoo.com/neo/groups/DigitalBlackandWhiteThePrint/conversations/messages/109150 )
I have now had my Sony a7rii converted by KolariVision using a cover glass that matches the OEM Sony glass thickness. Thus, while the original conversion used a thinner cover glass that was good for Leica M lenses, it did not work for Sony/Zeiss lenses made for the Sony platform and thicker cover glass. The new, thicker astro-glass conversion does work with the Sony & Zeiss glass.
See http://www.paulroark.com/BW-Info/KolariVision-Astro-BW.pdf for a summary of my documentation of this experience.
If you do the type of landscape photography that benefits from a dramatic sky, then this appears to be a major step above the stock solutions. I will report my experiences with this setup in the above PDF, with major findings noted here.
Happy Holidays to those who have some type of solstice celebration.
Paul