Archived posting to the Leica Users Group, 2004/05/04

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Subject: [Leica] Re: "Normal" lenses
From: ericm at (Eric)
Date: Tue May 4 06:39:23 2004
References: <007101c430ab$ddfb6ec0$3201a8c0@AUG01> <000001c430b1$c1a4e390$6501a8c0@dorysrusp4>

I suspect the flat field vs. curved one is more of a theoretical problem
than one from the field for landscape work.

After all, most landscape shots aren't shooting a straight wall from 5'
away.  Just some quick back of the napkin figuring...

The angle of view for the 35 'cron is 64 degrees.  So if you're standing 20'
from a wall, you'd be 23.5' from the left and right edges of the wall
included in the field of view.

For the 50/2, that would be 21.5'.

Since I started, I might as well finish.  So I found a DOF calculator.  At
20' at f2, the 35mm is sharp from 16 to 28 ft; the 50mm, from 18 to 23 ft.

That's also assuming the curvature of the field is spherical, which would be
worst case.  It's not completely flat, but it's not completely spherical,
either.  Most landscapes aren't shot at f2, either.  :)


Replies: Reply from timatherton at (Tim Atherton) ([Leica] Re: "Normal" lenses)
In reply to: Message from ruben at (Ruben) ([Leica] "Normal" lenses)
Message from dorysrus at (Don Dory) ([Leica] "Normal" lenses)