[Leica] KolariVision Astro-photography cover glass, Sony a7r, Leica glass

[Paul Roark]

I have updated my PDF on the astro-photography sensor cover conversion for
B&W.  See http://www.paulroark.com/BW-Info/KolariVision-Astro-BW.pdf .

The update covers my initial views/tests of a thicker (standard thickness)
extended red sensitivity cover glass that I had Kolarivision put on my Sony
a7rii.  This allows the Sony/Zeiss lenses made for that platform to work as
expected.

To summarize, Kolarivision now has 2 thicknesses of this astro-photography
cover glass.  One is thinner than usual, but still not as thin as the Leica
cover glass.  Nonetheless, the thinner cover glass is better for the M
lenses than the standard thickness glass.  The Sony/Zeiss normal and wide
angle lenses did not work well with the thin astro glass.  The new Zony
lenses assume a specific sensor glass thickness and build that into the
overall optical design of the lens, presumably because it allows more
compact lenses than simply adopting a retrofocus design.

The new astro cover glass which they put together for me matches the Sony
cover glass optical thickness, which is very good for Zony lenses, but not
as good for M glass as the thinner version.

In any case, for dedicated B&W, I personally think the extended red cover
glass (think old Tech Pan) is a better approach than a monochrome sensor,
at least for me and my landscape types of photography (no so for street
work).  For me the ability to do multi-color filtering in Photoshop is very
important.  The color, which needs the white balance at about 2900 is
somewhat reminiscent of old Agfachrome.

FWIW,

Paul
www.PaulRoark.com