Archived posting to the Leica Users Group, 2015/11/24

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Subject: [Leica] M8 type cover glass on a Full Frame body
From: roark.paul at gmail.com (Paul Roark)
Date: Tue, 24 Nov 2015 18:23:32 -0800
References: <CAJ3Pgh7+j3yJajsYWsZ4eoxKLUq2tSZTd79NLA3O_MVeTPh93A@mail.gmail.com> <D27A5FCA.4E2DD%mark@rabinergroup.com>

The closest thing I have found to a digital "Tech Pan" type of rendition is
the Kolorivision Sulfur ii cover glass for astrophotography.  I've put a
comparison of the TP v. Kolorivision cover glass spectral responses at
http://www.paulroark.com/TechPan-v-Kolorivisio-Sulfur2.pdf .  The vertical
axes are different, but the general idea, as well as target market, is the
same for both the film and now this digital response to the astro group.
The Kolorivision cover glass can be put onto a number of cameras, including
the Sony a7r.  If a normal spectral response is needed from a converted
camera, they have a filter for the front of the lens to do that.

I did not find a comparable M8 spectral response curve.  Kodak has removed
the original information from the web.  This verbal description of the
response curve gives some insight:  "...substantial response in the red
channel from 650-700nm and continued response out to about 725nm." (
http://diglloyd.com/articles/Infrared/LeicaM8_infrared.html#SpectralResponse)
But, it's really a bit too vague to know.  It'd assume the response in the
650-700 range is substantially below the TP or Sulfur ii levels.

Paul
www.PaulRoark.com


In reply to: Message from roark.paul at gmail.com (Paul Roark) ([Leica] M8 type cover glass on a Full Frame body)
Message from mark at rabinergroup.com (Mark Rabiner) ([Leica] M8 type cover glass on a Full Frame body)