Hi Michael, there are 2 problems I've been having.
(1) Focus is just wrong - I photograph buildings and interiors its rare that there isn't a high contrast subject for me to lock on to somewhere in the frame. Even with a high contrast subject in good light the focus may be wrong.
(2) Distance Scale is wrong - Because the AF circle is so large, if there are multiple subjects at different distances within the circle it gets confused and while it may lock focus, it might not be on either of the 2 subjects; and so I use the distance scale on the lens or LCD but this is also wrong.
In a previous post are pictures (1) photographing a black can on a white background with the 70mm. The camera confirmed focus but you can see the can is clearly out of focus. (2) I photographed a building 500m away and used the distance scale to set infinity. Building was out of focus. When I used live view to focus the camera said the building was 8m away. A BIG difference!
I'm trying to be fair and not saying the AF system in the S system is completely wrong; every AF system has it's limitations. All I can say is that from my experience I can NEVER rely on it except when using live view. I used my 10 year old Blad H3DII a few times recently and it has no problems nailing focus in more difficult lighting situations than the S. The distance scale on the lens is also reliable so if I turn the lens to infinity, I can be sure that a building 500m away is in focus.
Leica think I may have a lemon and so I'm still discussing with them how to resolve the situation.
Justin
On 1, You use
"focus maybe wrong" , I assume you can lock focus right sometime, this match what I see. The focus is more sensitive to vertical line than horizontal line in my field test. And I find critical focus is not consistent to fully appreciate sensor and Lens capability of. For f8, f11 stuff, I am fine as I can see focus myself if AF is wrong. just need slow down.
As for wide AF spot, yes, that is one of my biggest complain. There is no way you can nail the focus on eyes instead of eye slash with wide aperture, you don't know how AF algorithm implemented, is definitely not the cross point as you would think but whole circle, which is super stupid IMO. That is why I mentioned in my previous reply that subject distance for AF to work is important at wide aperture because at those distance DOF will cover the AF tolerance.
As for LCD distance scale, I would suggest you test other lens as well, it could be your particular lens problem. for the time I have S007(about 4 month), I don't find big error like yours, but I don't find it useful as well, I test 100cron at infinity, if I use it(screen) to focusing, I got inconsistent results. most of time, it is off.(not a lot but not sharp) I didn't test on 35mm Summarit, or anything wider(I have 35 but don't have SWA S lens), but you know the focus accuracy requirement is night and day different compare 24mm f3.5 lens to 100mm at f2.
So I guess this is most likely use for wide DOF stuff such as landscape, or long range subject focusing distance. However, I don't trust it as I don't know how this be generated, by AF rangefinder or by physical lens barrel location? In field, I don't need this gimmick, what I want is a reliable focusing so that I can focus at WO and shoot at shooting aperture. I can decide DOF and using aperture per scene by myself. What this stuff for? Can you use it shooting in studio portrait? This is totally nonsense IMO.
All I want to say is this system require attention for AF and replace units may not be able to solve your problem but showing 8M for infinity is seriously wrong I agree.
Good luck
-Michael