[rollei_list] Re: OT:Walter Voss Diax cameras
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Thu, 22 Oct 2009 17:52:57 -0700
----- Original Message -----
From: "Eric Goldstein" <egoldste@xxxxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Thursday, October 22, 2009 5:24 PM
Subject: [rollei_list] Re: OT:Walter Voss Diax cameras
83 mm is the diagonal for 2-1/4 square.
I also read somewhere in the deep dark past that the f/2.8
lenses for
the Rollei TLRs were taken from 75 to 80mm because the
slightly longer
lenses would be easier to correct as faster optics. It is
reasonable
to assume that this was the case, as it makes sense from a
design POV.
Eric Goldstein
Exactly what I said:-)
I measured a couple of Rollei negatives (also a
Rolleicord IV film gate) and found they were exactly 2-1/4 x
2-1/4 so the calculated diagonal comes out about 81 mm. If
you use 6x6 cm it will come out nearly 85 mm but that is not
the size of the actual negatives.
There are cases where the "nominal" film size is not the
actual film size. This is especially the case for sheet film
of 4x5 and larger. The film is smaller. I think this may be
due to the film being intended for use in plate holders with
adaptor sheaths but that would not explain why smaller sizes
are the same for nominal and actual. Perhaps its because
they came along later in the history of film. I think glass
plates are actually the nominal size but have none to
measure.
The difference is significant, for instance the
calculated diagonal of 4x5" is 6.4 inches (about 163 mm)
while the actual image diagonal is only about 152 mm.
--
Richard Knoppow
Los Angeles, CA, USA
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: