I was stalking a particularly 'flighty' butterfly yesterday; I had my 200-500mm (@420mm) and a TC1.4Eii on a D850 and managed a few OK shots, but it's a lot of kit to wave at a poor butterfly even at 6ft....and handholding, even with VR, has its limits.... ~420mm is as far as works for me...If I go to 500mm the IQ really drops off on my copy. EXIF records as about 650mm. Long axis captures ~ 110mm...so that gets me to about 1:3.... @ 2.2m What do other people use for such relatively small flighty beasts at medium/long distance? I've heard the 500mm PF doesn't play nicely with TCs, something to do with the PF elements? Even so, how about the 300mm PF?