Archived posting to the Leica Users Group, 2015/11/18

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Subject: [Leica] IR sharpness issues
From: george.imagist at (George Lottermoser)
Date: Wed, 18 Nov 2015 08:55:41 -0600
References: <>

If I had to guess?
which I do?

You're looking at a combination of:
Slow shutter speed
Branches moving in the breeze
Improper focus
A reduction of micro contrast in the IR range

The focus issue stumped me too
until I ran the tests
and locked in on a specific lens
which performed well with IR on M8
and found that magic focus shift point on the lens barrel.

Using that focus shift point
has a profound effect at all focus distances
even on subjects 200 meters away;
which surprised me.
Because you'd, or at least I'd, have thought
that "depth of field" would have made its use negligible.

And the testing also demonstrated that it is a precise point on the lens 
Even slight variations left or right of the "the point"
DO have an effect on "focus."

a note off the iPad, George

On Nov 17, 2015, at 3:33 PM, Howard Ritter <hlritter at> wrote:

> Any thoughts on the dramatic difference in sharpness between the two?

Replies: Reply from hlritter at (Howard Ritter) ([Leica] IR sharpness issues)
In reply to: Message from hlritter at (Howard Ritter) ([Leica] IR sharpness issues)