I was going to ask you much the same question, Keith, about your Indian Collection.
Clearly, different light and different subjects make direct comparisons impossible, but that aside, do you note any basic colour differences between your Leica and Zeiss glass?
As I've mentioned before, the only Leica experience I ever had was at my last empoyer's in the winter of '65. I remember we did some room sets for BBC TV up in the Glasgow studios, using an M3 and one of the 21mm lenses, but I can't remember if it was the Schneider or Leitz version. I remember this especially, because all the other 135 work was shot on Nikon F, and the prints that I made from that Leica film were certainly different to the Nikon images I also printed for him. So much so, that I kept a print for my own portfolio when I was about to quit.
So there you have it: same films, same processing and same printer using the same soups, yet the Leica look stood out. Pushed to describe it, I'd offer that even just printed up whole neg onto 8x10, it gave the appearance of having come off 6x6 film. It was something about tonality, nothing to do with crispness of optics.
So, yes, for this non-Leica owner, I do subscribe to the belief that there can be a noticeable difference.
Rob