[rollei_list] Re: rollei focus adjustment questions
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Wed, 7 Jun 2006 08:25:15 -0700
----- Original Message -----
From: <chatanooga@xxxxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Wednesday, June 07, 2006 3:37 AM
Subject: [rollei_list] Re: rollei focus adjustment questions
Hi Richard, listers
Thanks for all your input here. I'm still a tiny bit
unclear though: lets
say that the taking and viewing lenses are not coincident
( mechanically
so) but that at infinity the taking lense is perfectly
focussed. For this
final adjustment is a collimator still used or is the
tech more likely to
use the ground glass on film-plane techniques mentioned by
a few people
here?
rgds
Chat
One can set the infinity stop perfectly well with a
ground glass in the back of the camera. The autocollimator
is perhaps more precise but its main virtue is convenience
for factory adjustment.
To match the lenses you are still working with the ground
glass in the finder. Either adjustment can be done first
because the coincidence adjustment can be done at any
distance. However, its usual to do the infinity stop first
and then adjust the finder to match on a target at infintity
or using a collimator, which is an optical device that
produces a target that looks like its at infinity.
If the lenses are not very closely matched in focal
length they will agree at only one distance, not a very
useful condition.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
---
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