theres is none, ive tried it. ive been searching the net extensively and no one has discussed this. i panned the camera so fast beyond any situation in the real world.
the camera shop guy was so right that a square open gate sensor would be amazing even for stills.
I wanna see. Compression (or expansion) should occur, it just may not be easily noticeable. You have to measure fence height and rails width and so on.
You hiding something? :)
Well, measuring distances on your images (one slanted, another straight) gives about 6% of horisontal compression on second. Due to the distortion precision is low, +/- 2% or so.
His choice of subject matter and panning speed is one where horizontal compression/expansion would be least noticeable. With a known face, or what is supposed to be a square or circle, the effect will be more visible. With 800mm and a 16ms rolling shutter FF, I get unequally spaced horizontal repeating lines in landscape mode just from the slight vertical sway of the lens during the roll, without panning. The faster one pans, the more consistent the speed, I think, so unevenly-spaced vertical lines are probably more common with slower pans, which are less consistent due to a lack of inertia and more of a direct control.
conclusion. when panning the is no evidence of rolling shutter in portrait mode. in either the subject or background.
when shooting a car moving fast and not panning there is compression and expansion in portrait mode.
so if your shooting video or sports you can shoot in portrait mode following the action with no rolling shutter effects at all.
What about a wheel tat isn't moving? If you pan a moving bicycle in portrait mode, there should be no expansion or compression if you perfectly track the wheel with your pan. It is the wheel of one parked bike while you are panning something else that would compress or expand.