Some time ago I noticed the focus made a clicking sound when panning with a camera in video mode . In my case a Nikon D800. Well I have had another go to see what I can do to prevent it and found the answer. Put the camera in AF mode and the lens in M mode. Simples. The video below was with the D800 and a 24-70mm Nikon f.2.8 lens. No focus clicking but stll in same mm focus as I pan around my garden. Did not even need an extrnl mike , this was with the built in one on the camera. Needless to say having found the answer i shall be using the video side of the camera more. Whilst having a little play I do have Adobe Photoshop Elements11. Again having a little play with it I found it was very easy to alter the brightness /contrast etc within the program. I had (not in this video) One bit very light and the other normal , by finding somewhere in the middle of the video it was easy to get a more even light across the whole movie. So in my opinion it is one bit of editing kit as a must have. below taken hand held