I just posted a few F*300 examples on Driline's thread:
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/258324-tele...m-range-2.html 
Originally posted by Driline 
Very nice lens. I'm jealous. How does the auto focus work for you? Is it quick enough for birds in flight?
I can't say about how it does with BIFs, since I don't do that. But I can say that you may need to upgrade your body for best results. K-5 II/IIs focuses noticeably better; K-3 is even better than that. I haven't felt the need to upgrade to K-3 yet, since the K-5 IIs has been doing the job. But if I start to need a higher volume of demanding AF shots again, I'll look to upgrade to the K-3 or whatever may follow it. You'll miss (or completely loose) focus more often on a DA*300 on a K-5 compared to the F*300 (especially if you put the F*300 on a K-5 II or better).
Most people need to upgrade their lenses and not worry about the body. If you get adequate performance with the K-5 and one of the 300mm lenses you're looking at, then you're OK. But in your case, since AF performance is one of the big upgrades with the last two generations of Pentax bodies, you should consider another body too.
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