Thanks for reply, Colin. Great shots. Are they cropped? I did some hand held tests and was amazed at sharpness at 600mm. It was the ball at top of a nearby flag pole. At extreme crop the braiding of some frayed threads on the rope was resolved, and that was impressive. Recalled the amazing sharpness of a Sigma 50mm 1.4 I once tried. I will definitely try hand-held on some real subjects before I decide on a gimbal to see if I can get good results.
Hi Tom yes they are large crops