To still get excellent results at f/22 is quite remarkable. At 150mm, central sharpness is very good at f/2.8 and excellent from f/4 through to f/22. The edges are just fair at f/2.8 and very good ...

The edges are fair at f/4, very good from f/5.6 to f/11, good at f/16 and fair at f/22. At 150mm, the centre sharpness is fair at f/4, good at f/5.6, excellent at f/8, very good at f/11 ...