Archived posting to the Leica Users Group, 2000/04/06

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Subject: [Leica] LF DOF <OT>
From: Jim Brick <jimbrick@photoaccess.com>
Date: Thu, 06 Apr 2000 09:13:47 -0800

At 11:45 AM 4/5/00 -0700, Mark Rabiner wrote:
>
>Jim as long as we are kinda talking large format please give us a quick
rundown
>on how you tilt to get the foreground in focus after focusing at the
horizon or
>visa versa depending of if you are using drop bed bottom tilt or center axis 
>tilts.
>I've been shooting sepia Polaroids with my Cambo trying to get the bugs out! 
>Fun!
>Mark :-) Rabiner

Well... with the Linhof Master Technika that I had, I focused half way
between near and far, tilted a little, checked the focus, and repeated
until it was where I wanted it. It is actually fairly quick (with
practice.) There are no degree or millimeter markings on the MT.

With my new Linhof Technikardan (TK45) I have been using a measured
scientific method since this camera has measure and degree markings
everywhere. Focus on the near point (note measure on rail), focus on far
point (note measure on rail). Subtract. Either estimate or measure (I have
a little mm ruler but estimation works pretty well) the distance between
the focus points on the ground glass. Divide the GG distance into the rail
difference (everything is in millimeters) and multiply by 60. Set the front
tilt standard to that number as the answer is in degrees.

Rail focus difference is 14mm.

Distance on ground glass is 70mm

60(14/70) = 12

Tilt the front standard 12 degrees.

Refocus.

Set exposure.

Take photograph.

Jim

PS. Reference... Robert Wheeler at  http://www.bobwheeler.com/photo/