Peculiar focus issue on Ultron 35mm LTM

[nano.anderson]

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I took some photos at the Whitney the other day. This photo of Shapolsky et al displayed some peculiar focus on the right side of the photo. Looking at the text, it looks like there is motion blur on the text on the right, but not on the text on the left. Is this just a common type of focus blur on wide-open, wide-angle shots? Or could there be something going on with the lens or camera (M9)?

Edited August 27, 2015 by nano.anderson

[250swb]

With the lens being wide open it looks like a simple case of you aren't standing square to the wall. If possible stop down more, or at least do a series of shots so one ends up being in focus across the plain.

 

FWIW rangefinders do need a few extra shots for safety on certain occasions, the only other consideration being that perhaps a lens element is off centre, but that is unlikely as you'd see it in normal pictures as well.

 

Steve

Edited August 27, 2015 by 250swb

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[fiftyonepointsix]

I had to tighten an internal retaining ring on my 50/1.5 Nokton Asph in LTM; used a pair of needle nosed pliers to reach into the ring as it screwed into the threads. Someone probably used a flathead spanner before me, was not completely tight. After that: no issues with intermittent blurry images. The 35/1.7 Ultron is similar construction. I only bring this possibility up as I have not seen it documented elsewhere.

 

I would shoot another test, with the object placed symmetrically in the picture. Try it with the lens pointed down, then the lens pointed up. If there is a loose element, there will be a noticeable difference. If one corner is always off, it is possible that a lens element is misaligned.

Edited August 28, 2015 by fiftyonepointsix

[nano.anderson]

Thanks for the advice! I'd never noticed this issue so didn't bother taking multiple test shots, but I certainly will now.

[uhoh7]

A decentered voigltander lens is not uncommon.

 

I'd do a proper infinity landscape at 5.6 and check sharpness across the frame.