Below is the email I wrote last year. The different between 2-4 and 1-4n is
up to 1.5EV, more close to the human observation.
C.H.Ling
=====================================
From: C.H.Ling <chling@xxxxxxxxxxxxxx>
To: olympus@xxxxxxxxxxxxxxx <olympus@xxxxxxxxxxxxxxx>
Subject: Re: [OM] Cleaning Screens
Date: Wednesday, April 21, 1999 9:37 PM
There were some threads concerning the brightness of focusing screen before
without any conclusion, here I have some data just measured with my OM4Ti
and 50/3.5, target to a light color wall, place a light meter behind the
viewfinder and take some readings with four different FS (with comments on
the smoothness of screen) :
OM4Ti with
OM 2-4 --- 4 +0.6EV (extremely fine)
Minolta 7000 --- 4 +0.3EV (fine)
Canon EOS 620 --- 3 +0.7EV (very fine)
OM 1-4n --- 3 +0.1EV (coarse)
OM2n with Canon EOS 620 screen --- 4 +0.2EV
Other observations:
- With large aperture lenses, the brightness between different FS is less.
Some people said the OM series 1 and 2 screen look no different, they might
have used a 50/1.4 and compared with OM4 and OM2n.
- Minolta 7000 FS is not as bright and fine as OM 2 series FS but focus
better with large aperture wide angle lenses.
- I own a Beattie screen before, (by memory) it is very similar to Minolta
FS, but it vignette with my 16mm fisheye. If you can find a used Minolta
FS, it is a more cost effective approach.
- The finer the screen the better it works with small aperture lenses, a
200/f4 with 2X-A works very well with the OM 2 series screen, but not so
good with large aperture wide angle.
The Canon screen I damaged is the best I have ever seen, it is extreme
fine, the brightness is close to the OM 2 series screen but focus equally
well with wide or tele lenses, I will try to find out what it is later.
C.H.Ling
-----Original Message-----
From: biesele@xxxxxxxxxxxx <biesele@xxxxxxxxxxxx>
To: olympus@xxxxxxxxxxxxxxx <olympus@xxxxxxxxxxxxxxx>
Date: Tuesday, September 19, 2000 7:05 AM
Subject: [OM] Re: OM Screens
>If you've done the 50 F3.5 could you send me the
>results or repost them?
>
>I'll try an 80 F4 at 1:1.
>
>Quoting C.H.Ling
>"You should also try a F3.5 or smaller aperture lenses,
>I bet the 2 series screen will be the winner. Large
>aperture lenses are less affected by a bright screen. I
>have posted similar test before with Zuiko 50/3.5."
>
>
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