Originally Posted by Roger Hicks
It comes back yet again to the 'quality threshold'. Once a camera delivers results that are 'good enough', then they're, well, good enough. My old Pentax SV with its 50/1.4 is 'good enough'. After that, for me, it's usually down to how happy I am using the camera: to how easily I can use it to get the pictures I want. If I want the ultimate in quality, after all, I can always switch to a bigger format. All the stuff about 'Leica glass' is usually irrelevant.
I agree within a format to an extent. It's true that if I took a generic image from my ZM Ikon and Nikon F100 and put them (negative/scan/print) side-by-side, I wouldn't be able to point to a superiority between one or the other. Or, for that matter, my $20 Yashica GSN.
But the exception is in the details. I can absolutely tell the difference between images from my Nikon 35mm f/2 and my Zeiss 35mm f/2. For the kind of photos that I like to take, one has characteristics that make it essentially unusable, while the other is near-permanently attached to its camera. For another focal length, my Nikon/Ikon preference is reversed. I'm not concerned with LP/mm, but there is absolutely a quality difference that guides my equipment choices over and above how much I like using each individual machine.
But yes, if image quality really matters, then I'll use my Fujifilm GX680III. There are very few IQ problems that ten pounds of SLR can't solve.