I acquired the Kowa 500mm Telelens with adapters for Nikon,Pentax and M4/3 systems.
Here are some images with different cameras on the same objective.
D7100 - Kingfisher about 150feet.
Pentax K-30. I bought this camera for it's focus trap in manual mode.
I really like this camera with focus peaking. Makes manual focusing easy as the bottom image would show.
Needless to say I had a lot of fun shooting with different configurations so much so that I am thinking of adding Swarovsky and Sony to my arsenal.