[Sylvain]

I do own have a Zeiss Biogon 28mm f2.8, and do not have my/any 28mm f2.8 with focus scale at hand, but here are a few questions and some thoughts.

If I understand correctly, when you disregard the DOF scale stuff, and really focus at 2 meters on a subject, at 5 meters on a subject, or anywhere in between, you get out of whack results?

Or, you only get soft results when not focussing on something through the view finder, but when you try to guess the distance and set the distance via the focus scale things look soft?

You might get better results not using hyperfocal distance (regardless of which lens) and instead focus at infinity (with an appropriate aperture choice).
https://luminous-landscape.com/digital-f...-part-two/

A familiar name :-)
It's hard to give you a hard confirmation because that's precisely the thing I could not formally test. Poor testing protocol on my part as I was not very comfy with their olive M10 Safari in the streets of a so so area.
I've ordered an m to mft adapter to be able to do further digital testing of that but in the meantime, I'm curious as if this sort of "in between" dud was normal as a defect (thus not by design, where it is sometimes known that a lens perform poorly at some ranges of focus/zoom). I may be naive but I don't quite see how just the mid range could be defect but I sure hope zeiss didn't design it this way.

My assumption was that, given hyperfocal properties, I could indeed set the focus mark between 2 and 5 (use case was street photography) and eventhough in most case, subjects would still lie further than 5 meters, they'd still be sharp thanks to hyperfocal shooting.

I understand your question about the rangefinder but it's not strictly a rangefinder issue I'm afraid. Close distance and infinity tests indicate no notable bias.
As for getting better results at infinity, it's true that given the dof scale, it would still be rather workable (and indeed the digital tests shots at infinity were plenty sharp up to close enough : still getting DOF from inf to 3-4 meters at f8 but I'd find that a bit disappointing in practice.



Thanks already for the first input (and interesting article),