Originally posted by Rupert Can't speak for the K3 but the K1 is head over heels better AF than the K5IIs and it was pretty decent.
I don't see it yet when I test K-1 AF.C on flying birds and running squirrels. It also depends on lens, I guess. Old Tamron 90mm macro has the same terrible AF ability on K-1, but I use it for MF macro anyway.
DA 70mm ltd is good, and seems faster focusing than FA 77mm f1.8. I love them both for portraits, but it seems that 70mm benefits more on FF (personal opinion), while 77mm is simply very good at any format.
Also, wth K-1 I noticed moire on bird's feathers, first time ever. Must be because of bigger sensor. Seems like sensor filter simulator minimizes it, pretty handful feature.
One thing about ergonomics of K-1 is pretty upsetting, my right big finger hurts because of bigger (deeper) groove on the back of the camera.
I keep K5iis for birding and wildlife.