[ATM] clave eye relief

[John Lynch]

Jerry et al.,
 
However, I found a reference to the 10mm Clave having
a 3mm eye relief, which does NOT follow this rule.
 
John

--- On Sat, 10/10/09, Jeremy Royston <jroyston at gmx.de> wrote:


From: Jeremy Royston <jroyston at gmx.de>
Subject: Re: [ATM] clave eye relief
To: "'D ERIC ALLEN'" <ericandroberta at sbcglobal.net>
Cc: atm at atmlist.net
Date: Saturday, October 10, 2009, 2:32 AM


Hello Eric,
    Your reply is a good example to all - looking at the literature
saves a lot of discussion. 
Luckily the second edition of Texereau is next to the PC. On p. 221 it says
"The object focus and the eye point are at 0.73 of the focal length relative
to the external lens faces..." 
Every mirror maker should have this book and obey it

Best wishes, Jerry

-----Ursprüngliche Nachricht-----
Von: atm-bounces at atmlist.net [mailto:atm-bounces at atmlist.net] Im Auftrag von
D ERIC ALLEN
Gesendet: Freitag, 9. Oktober 2009 16:38
An: atm at atmlist.net
Betreff: Re: [ATM] clave eye relief


Hi John.  Texerau says eye point (which I take to be eye relief) is 0.73 of
focal length in the Plossl.  Gerald North says "about eighty percent", but
it sounds like Texerau actually measured it.
Eric Allen
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