Originally posted by lancer3397 forget using a TC with the 55-300 unless you are birding or looking at something fairly static. I tried the 55-300 combination on both the K-X and K30 for airshows and it just hunted and hunted and hunted. you lose too many fstops for airshow work with that combination. On a really bright day, maybe, it might work but you are better off going Manual focus and birding or something slow moving.
but get a nice 55-300, with good light and the right conditions and you will still get some stunning photos from that combination.
It can be done.
Using the 55~300 at 300mm on a K3, I successfully achieved focus lock on
flying Bald Eagles at approximately 150' altitude handheld in AF.S, single center AF point. Granted, this was against a bright clear blue sky but they were really up there. 200% mag (16x) only fills half the LCD.
Testament to the new K3 AF system.
My wife later told me I kept saying, "GOT him!"