Lately I have been photographing red flowers (roses & cactus-flowers) using Fuji Superia 400 ISO and Kodak Ultramax 400 ISO, using several different cameras (including a digicam) as well as different lenses. What I have noticed is that while all lenses appear to have difficulty in resolving (focusing) the details of the red (as opposed to other colours) petals and flowers, some lenses are better at it than others. Some render the centre of the flower as an undifferentiated red smear. In particular, I have noticed that "venerable" German made (Color Skopar Voigtlander and Zeiss) lenses -even if "cell focusing" appear to be better at it than many of my Japanese made lenses (Minolta, Canon). Is this just my imagination and lack of technique or does this have something to do with lens construction? Is anyone else aware of it?