Gisle Hannemyr wrote:

Which one is the best (resolution, contrast, colour)? [...]

I just got myself a used Praktica with a Pentacon auto 1.8/50 multi-coated
lens. I haven't taken any pictures with it yet, but I noticed that the
diaphragm blades on the lens are much more glossy than on my other lenses.
I assume that will affect contrast, especially at medium and small
apertures, as light reflected from the film will be reflected back by the
diaphragm blades.