Yes, I'm sorry Jarrod, you are of course correct. I always use 16:9 with the XL2 and expect the same problem would apply when in 4:3 mode - I know that I also used to sometimes have similar problems with the XL1s (4:3).

16:9 shouldn't make any difference, although it does add vignette problems when using some add-ons (compared to 4:3).

The IS ‘drag’ of the 20X can also sometimes cause a slight momentary vignette at the edges when combined with a wide converter during movement or a slow sideways pan.