I use the K-7 (my first DSLR) and shoot a lot of Karts at my local track, the slow AF is a real pain, very often by the time the camera has focused and the shot fired the first kart has moved and the second one is in focus. Shot wasted
I love my camera and the fact that the other photographers go running at the first sign of rain, but the slow AF is very frustrating, and the ability to continue into almost dark with that awesome ISO range and still get crisp shots is a definite plus. If you get the K-7 you will be constantly beating yourself up for not pushing the boat out for the K-5.
Family holiday in March and as soon as I'm back I'm saving to part ex for the K-5.

PM sent re the Lowepro Rezo 160AW bag

How do i do the PM thing, I would quite like the bag if it is suitable for my kit.

I second rparmar's comment I bought one from ebay £45 and boy is it good I also use it for reverse macro

Hi Ivan and welcome to the forum, I would recommend any Pentax 50mm at around f1.7 or less, loads on ebay, and if you make sure it is manual it will teach you more about how to setup your camera correctly.
Enjoy your Pentax.

Good point ... well made. I didn't think that using a TC on a zoom was any good. Can anyone post a link to some examples with both AFA1.7 & *60-250 please.

Thanks.

Thanks for this clarification, I did think that there must have been something wrong because most of the sample shots I'd seen appeared pin sharp (for example). Apologies if I have upset anyone.
So I am now coming round to the idea that the *60-250 is the way to go and for distance maybe a *300 with a TC.
Thanks for your help as always folks.
But I still have an inkling for the Bigma

I'm back again.
I found this comparison on flickr and wondered how accurate you guys reckon it is? From the images it appears that the 60-250 isn't that good until you get up to f8 & the 50-135 might be considerably better and for distance the *300 or *200 and possibly a teleconverter?

I've looked on flickr and I'm not that convinced that any of the Sigma 500mm zooms are that sharp unless conditions are perfect and I would be gutted to spend that amount of money and get soft images.
Utterly confused

So what I'm probably looking at then is a 60-250 to cover the closer stuff and then maybe later on poss next year a siggy 500 but the 150-500 hsm not the 50-500. unless Pentax bring out something around the 400mm range in the mean time ... now wouldn't that be nice

Slow to focus ... aaaghhh
you are slowly bringing me round to the 100-300 + tc it is V important to get the fast focus.