I was using my new Sigma 150-600 on my trusty old manfrotto 055xprob w/ 488RC2 last weekend to take some pics of the moon, and also popped the canon 2x extender on there for good measure. I think it captured some decent pics, but noticed that it was very difficult to position using the ball head.
I would loosen the ball, line up the moon, tighten the ball again, and then the weight of the lens would pull it down and I'd lose the moon out of the view. I'm thinking either the 488RC2 is either not big enough for this? Or maybe balanced on a gimbal head would be a better solution for the size of equipment I'm working with now.
Also noticed lots of vibration / bouncing whenever I would let go of the camera after setting up the shot. Is that something that would be fixed by changing the head, or is a carbon fiber tripod a better answer (or just a waste of money!)?
Edit: Here's a crop of the moon I took at 1200mm with the 150-600 and canon 2x extender. I think it's decent, though there is some blur to it. Not sure if it's due to the shutter speed, or vibration of the mount.