[rollei_list] Re: AW: Re: Rollei 35 mm SLR Flange focal distance
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Tue, 9 Sep 2014 16:39:52 -0700
----- Original Message -----
From: <Dirk-Roger.Schmitt@xxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Tuesday, September 09, 2014 1:39 PM
Subject: [rollei_list] AW: Re: Rollei 35 mm SLR Flange focal
distance
Emanuel,
thanks a lot, but this information confuses me totally!
I do not understand what a lens vertex is.
In the light from Carlos' information I do not understand
the 44,67 mm for the focal point.
Second: From that, what Carlos was writing, the 44,67 mm are
the distance from bayonet seat and pressure plate plane.
I looked at two of Rudolf Kinglake's books on optical
design, the term "flange focal distance" does not appear in
the index of either. Nor can I find it in the Optical
Society handbook. Very odd because it is a common term. I
think the above is the correct definition, that is, that its
the distance of the locating reference plane for lens mounts
to the focal plane. Back focus is something else and is the
distance from the vertex of the last lens surface to the
focal plane when the lens is focused at infinity. I think
the definition will hold even if the last surface is concave
to the focal plane. The two are only incidentally related.
In a camera using a range finder the flange focal distance
is important because it affects the accuracy of the
rangefinder. I have a somewhat hazy memory that the bayonet
mount lenses for the early Nikon cameras would fit onto a
Contax, and vice-versa, but the flange focal distance was a
little different so the rangefinders would not work
correctly.
--
Richard Knoppow
Los Angeles
WB6KBL
dickburk@xxxxxxxxxxxxx
---
Rollei List
- Post to rollei_list@xxxxxxxxxxxxx
- Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe'
in the subject field OR by logging into www.freelists.org
- Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with
'unsubscribe' in the subject field OR by logging into www.freelists.org
- Online, searchable archives are available at
//www.freelists.org/archives/rollei_list
Other related posts:
