Robotar (Kobori) MC 28mm f2.8 VS Tefnon (Kobori) MC 28mm f2.8

▼Taken with Robotar (Kobori) MC 28mm f2.8 + Pentax K100D Super

▼Taken with Tefnon (Kobori) MC 28mm f2.8 + Pentax K100D Super

Both photos were developed with UFRaw (Gimp 2.8). The files taken with Tefnon were suitable to the Auto White Balance of UFRaw and thus I applied it. My Tefnon seems to be the latest version (5 groups 5 elements). Compared with it, my Robotar is a bit longer in length and I just guess it may be 7 groups 7 elements or otherwise 6 groups 7 elements. The Tefnon is weak in against light but good in shadow, whereas the Robotar is OK in against light but not interesting in shadow. Which one shall I bring that is the problem.

Incidentally, I took the same flower at the same place as below pictures, however the flowers look different this time. Is this a different tree than below? Or below flower develops or changes as time goes by?