This lens is almost comparably sharp as C/Y Vario-Sonnar 35-70/3.4, Vario Prakticar is better at corners
at 70mm end, at wide end Vario-Sonnar is sharper with slightly better contrast too. It is an amazing lens.
The Vario-Prakticar does it with 9 element 8 group, in which one is a flat glass, whereas Vario-Sonnar has
10 element 10 group, the both were introduced at mid 1980. They both conveniently have a macro mode.