In the end it is not likely just about how sharp a lens is, but about your photographs with a lens .
BTW, rendering is one of the reasons why I have taken a big liking to MFT these days.
BTW2: If I had know what I know now, rather than acquiring a 350D back at the time when I did, I would have gone straight away for a 5D, which was available as well at that time, plus some L-lenses . I would have saved myself a lot of money . Eventually I went that route anyway.
Kind regards, Wim
It seems we agree on a lot of things. And perhaps your experience makes up for the differences. Today shooting a set of photos of Honda's classic two seater, the Honda 2000. I discovered a couple of things. 1) You were right about FF. and 2) having the versatility of the EF 17-40L was a lot more convenient than climbing, and crawling, looking for the right angle. Maybe part of that was the fact that it was on a showroom floor, and not out in front of my house were I would be more comfortable taking my time.
A dear friend just passed away in December. We both photograph insects extensively, but he volunteered many thousands of hours for the Parks Service giving guided nature walks. Well, how can I put this humbly...I just assumed I was a better photographer, and the fact that I saw he had an Olympus 4/3 did nothing to dispel this notion. As it turns out he was better at just about everything than I was. But we loved the same things so we became good friends. After looking through his photos, I started looking at other Oly photos on the web. These little cameras are superb!
Now, I've heard you mention that you like to make large prints. Well, don't print much, and nothing larger than 81/2 x 11" We both know if you want to print large you probably need a larger sensor. Most of my photos, the first thing I do is to crop. I have to. My computer is not really fast enough (I'm impatient) to work on full sized photos. I usually save the original. But, hell, I might as well have a 16mp sensor! I thought the DLA (Diffraction Limiting Aperture) of MFT should make shooting difficult. Well, apparently the trick is to use lenses that start out fairly sharp wide open, and also to master the daytime fill flash. So Scott got his top of the line Olympus professional camera in November. I acquired a inner and outer bayonet adapter for Zeiss/Contax/Kiev rangefinder and had four lenses lined up. But I was too late! I never got the chance.
OK, sorry for rambling on. The one thing I wanted to say was Voitlander is serious when they say APO. Have you tried the APO Lanthars? I have the relatively pedestrian 90/3.5. And really like it. But what I really want is the Voigtlander APO-Lanthar 125mm f/2.5 SL with a native EF mount (though manual focus). This may well be the holy grail of lenses for me! I wish I had the chance to shoot my Zeiss lenses on the professional Oly. I don't doubt it is as you say, but I've never had the opportunity to find out.
And as a final hopeful thought on Zeiss RF glass...The size is perfect for the MFT cameras! I can't wait to try them! But then, I guess I have to!