Archived posting to the Leica Users Group, 2011/04/12

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Subject: [Leica] DOF of 80/1.4 at 1.4 slimmer than 50mm at 1.4?
From: red735i at earthlink.net (Frank Filippone)
Date: Tue, 12 Apr 2011 07:56:06 -0700
References: <BLU0-SMTP63FFBE73F8419F8D7EEA128CA80@phx.gbl> <C9C90568.D216%mark@rabinergroup.com> <BANLkTin1=bou3XDpDviKAsVQs4UnqRCnhQ@mail.gmail.com>

Consider that the correct focus is a FLAT PLANE... faces aren't.  If the
face is even slightly turned away from the camera, for an 85mm F1.4 lens
used at F1.4, one eye will be sharp, the other out of focus.  There is
basically no ( I could go look it up, but you get the meaning) DOF.
Only if the eyes are precisely square to the camera do you get both eyes
sharp.

In these shots, the body is twisted (she is facing to our right, but the
head is turned to be about square to the camera).  It is pretty possible
that the line ( or rather plane) of her eyes is not square to the camera,
thus making one eye in focus and the other not.

I would send the camera in for a calibration, just to be sure, but I doubt
there is going to be any changes.  The film plane of the camera would have
had to move relative to the lens mount.

Check to see if the springy plate behind the camera still moves flexibly,
and that the screws around the lens mount on the camera are all tight ( I
tightened someones'  mount screws last week...).

Frank Filippone
Red735i at earthlink.net


 there are plenty of frames on the 5 or so rolls I shot of Rachel that day
where the focus isn't right.  I used f1.4

 Marty




Replies: Reply from benedenia at gmail.com (Marty Deveney) ([Leica] DOF of 80/1.4 at 1.4 slimmer than 50mm at 1.4?)
In reply to: Message from vick.ko at sympatico.ca (Vick Ko) ([Leica] DOF of 80/1.4 at 1.4 slimmer than 50mm at 1.4?)
Message from mark at rabinergroup.com (Mark Rabiner) ([Leica] DOF of 80/1.4 at 1.4 slimmer than 50mm at 1.4?)
Message from benedenia at gmail.com (Marty Deveney) ([Leica] DOF of 80/1.4 at 1.4 slimmer than 50mm at 1.4?)