Hello Godfrey,
thanks for your comment, glad you enjoyed it. As far as the thing you question, I think that when testing lenses I have to "level the field" as much as possible between the lenses I test. Same adapter, same infinity position on the lens; if the results are different due to the optical design of the lens, i.e. one is better than the other
by design, so to speak, then the test will show it. If one looks worse than the other because its hard infinity stop is not exactly where it should be, and there is a workaround that makes it perform better, well - it would not have been fair to test it in the "corrected" position, IMHO, since if there is an infinity stop on a lens I expect it to be at infinity where it is
supposed to be at infinity, not somewhere else. Especially for a Leica lens, which I expect to be the pinnacle not only of optical design but also of construction and precision - and I pay for that excellence, princely, so I have the right to expect it. To me, if the problem is caused by the infinity stop being off, well - this too is part of a test result. More, suppose for a second that rather than being off on the side of infinity that you report, the lens were off on the other side: in that case, there wouldn't be any possibility of getting perfect focus at infinity... so, I think that my methodology is correct (as possible, we all are humans of course), and if you are right then Leica should pay better attention during their QC.
About focus past 0.7 m, that's not a big issue; I think it's actually helpful if you focus the lens on a M, but since I was testing both lenses on the SL I do prefer the Voigtlander seamless focusing action
on the SL compared to the Tri-Elmar.
Generally speaking, I think I am on the opposite side of the focusing fence: I rather prefer to use WA under 28mm on the SL than on the M. I find the focus magnification a godsend, making it extremely easy to focus a WA and Ultra-WA lens perfectly and no matter where you intend to focus it, getting rid of all the focus-and-recompose focusing errors that moving a camera creates (and that Hasselblad tried to fix in their MF cameras).
About the 15mm R, I heard only great things about, and if I will ever find a good copy you can be sure I'll get it immediately
Best regards,
Vieri