Archived posting to the Leica Users Group, 2001/02/10

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Subject: RE: [Leica] focus inaccuracies: my test results
From: "Dan Honemann" <danh@selectsa.com>
Date: Sat, 10 Feb 2001 20:28:31 -0500

Martin wrote:
> Essentially, you're both doing the same thing.  With the receeding ruler,
> you need to do the trig to figure out the true subject-to-film distance
> (since your basically photographing the hypotenuse of a triangle) which
> ultimately will probably result in a more accurate result than trying to
> figure out what exactly 1/16" is in terms of turning the lens barrel.

I cheated a bit and taped a page of newsprint just below the 6" mark on the
ruler (my point of focus) such that the page was parallel to the film plane
while the ruler was at an angle.  That way I could check both the in-focus
range along the ruler, the flat surface of the newsprint, and also measure
from the page to the film plane to determine actual focus distance.

Like so:

(ruler)
  /
 /---- (page of printed material)
/

  x (camera on tripod)

Dan (kooky photographer taking too many test shots)

Replies: Reply from Bernard Cousineau <flatbroke@sympatico.ca> (Re: [Leica] focus inaccuracies: my test results)