Archived posting to the Leica Users Group, 2007/04/16
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Eric,
Good for you! You are now master of your fate, captain of your ship.
BTW, now try your lenses at f/4. If there is any focus shift, it will
appear around there. At smaller f/# the increasing DOF takes care of the
problem. So, I either shoot wide open (f/1, f/2 as the case may be) or at
f/8, where all of my lenses are sharp as a tack.
If you look at the Leica technical papers (or your lens barrel), you will
notice that most of the DOF is behind the focus point. Here is a table for
the Noctilux focus at 5 meters (other 50mm Leica lenses should be similar
for same f/#). The distances are in meters. Notice that at f/8, 3/4 of the
DOF is behind the focus. At f/16, a whopping 98% is behind the focus.
f/ Near Far DOF Near % Far %
1 4.715 5.322 0.607 47% 53%
1.4 4.618 5.451 0.833 46% 54%
2 4.472 5.671 1.199 44% 56%
2.8 4.291 5.994 1.703 42% 58%
4 4.045 6.553 2.508 38% 62%
5.6 3.758 7.486 3.728 33% 67%
8 3.398 9.523 6.125 26% 74%
11 3.035 14.45 11.415 17% 83%
16 2.578 107.5 104.922 2% 98%
Bob Rose
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Message: 11
Date: Sun, 15 Apr 2007 15:37:39 -0400
From: "Eric Korenman" <faneuil@gmail.com>
Subject: [Leica] Fwd: more M8 Noctilux questions
To: LUG <lug@leica-users.org>
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<82c9dd70704151237r3bc30249v6af02c0f88cc469c@mail.gmail.com>
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UPDATE: With a deep breath and as slush fell from the sky (NE weather
right now), I took a 2mm hex wrench to my M8.
After about 20 minutes of fiddling and 50 or shots of distant street
signs and close ups of newspaper (!), my Noct appears to focus near
perfectly. My 35mm and 50mm crons seem to focus just fine as well.
It took the Noct to show me that the M8 was so slightly out of adjustment.
Eric