K10D to K5 upgrade?

Hi all I am thinking of upgrading my K10D to a K5 and before I do would like to ask a couple of questions.It will be used with a 50-500 bigma all the time and wondered if I would see a moderate or large difference and also could anyone give me an idea as to how much I would get for the K10D in part ex.
thanks
Graham

Huge difference.

My 50-500mm on the K10D was ok but due to the speed was only really useable in good light. With the K-5 it's like a different lens.

ISO 3200 with K-5 and the Bigma (handheld).



Chaffinch on feeder by Mike.Pursey, on Flickr


And in decent light...



Bournemouth Air Festival 2011 by Mike.Pursey, on Flickr

As for the K10D .. personally I would sell it on here .. you should get about £175/200 depending on condition/actuations. From a dealer I doubt you will get more than £150, if that.

Do it! You won't regret it for moment.

I upgraded from K10D to K5 in Feb and as Mike said it's like having a different lens. I use a Sigma 120-400mm and if, like me, you shoot a lot of wildlife you'll find that you can take pictures that would have been impossible before.

And yes, I got around £200 for the K10D

Thanks for the replies and I think I will bite the bullet and buy one.I am disabled and all the photos I take are from the car or from a reserve hide (RSPB Saltholme is just 10 mins down the road).Apart from the obvious AV ISO speed etc are there any other camera tweaks and setting you could suggest for wildlife photography,I have just recently started shooting in RAW and changed the AF to the button on the back.
Thanks
Graham