lens star test on 645z

645 DFA 55/2.8

F2.8: 

F3.5: 

F4.0: 

F4.5: 

Borderline OK for astrophotography, and definitely not excellent. It only becomes barely acceptable after stopping down to F4.5.

645 FA 35/3.5

F4.0: 

F5.0: 

Incredibly sharp in the center but has strong coma even when stopped down to F5.0.

67 90/2.8

F2.8: 

F4.0: 

F4.5: 

There is a sign of misaligned elements, as stars in the lower-right and upper-left corners are softer than the other corners. It is acceptable at F4.0, and fairly good at F4.5. The center is a little bit softer than the 645 55/2.8, but the corners are much better.

67 165mm/F2.8

F2.8: 

F4.0: 

F4.5: 

It's acceptable at F4, and quite decent at F4.5.