I wonder if you all have experienced this when you do long exposure (several seconds) using a tele zoom lens.
I am using a Sirui tripod and Markins ballhead. I fixed a Canon 6D and zoomed in to 135mm to take a shot. After that, I adjusted the exposure by turning the camera dial slowly and carefully. When I did this, I noticed from the viewfinder that there is a slight movement of the setup.This is despite me locking the ballhead tightly and the camera was firmly fixed to it. But it looked like the camera went back to its original position after that. I then took another shot.
When I reviewed the images on the LCD screen, I noticed the 2 images were not in the exact position. There was a very slight difference in position. So when I turned the camera dial, the camera must have moved, even though very slightly.
Is this commonly expected or does it mean it's time for me to consider a more stable tripod and better tripod head?
Thanks and appreciate your advice in advance.