Congratulations - I got one recently from SRS as the price was so good - it's a nicely made compact zoom that performs very well as long as you don't expect miracles. I'm glad I got one, and I'm sure you will be too.

I wouldn't differentiate much between Pentax and Tamron versions either - they are essentially the same lens and should perform identically. I've used both and if anything my Tamron performs better, but it's a pretty close call. Neither lens is at its best at full telephoto, but they perform well at the shorter lengths.

I don't know what kind of price you were thinking of paying, but if you can stretch to it, you won't do much better than the current Pentax 55-300 DA lens.

On the secondhand market, the Tamron 70-300 offers an awful lot of bang for the buck (very sharp but comes with some purple fringing on high contrast edges that you need to process out on occasion). Even new you might be able to find one of these for not much more than £100, and at that price I'm not sure I'd be that interested in looking for an old secondhand zoom from 10-20 years ago.

Finally, another old prime that is worth looking out for is the compact SMCM 135 f3.5. Really good examples should be in the £50 price range, and it's a great lens.

Don't know where you live in London, but I've had great service from SnappySnaps opposite Clapham Junction. Ivor Howell in West Norwood also supposed to be good.

Size wise very similar to K100D, but with much better grip. Weight wise feels more like (and perhaps more solid than) K10/20D. Combines great handling and ergonomics of the latter with the compactness of the former. Works brilliantly for me without grip (and I used my K20D with the grip to improve the handling!).

Glad it arrived safely. I'm afraid there's a bit of a queue for the 10-20...

Jon

Of course this does mean that Jacobs in Tottenham Court Road can offer a GX20 with 16-45 at a steal of a price if anyone else here is interested!

Yes - it's useful on occasion and can be good with things like tweaking white balance that can otherwise be hard with JPEGs.

10-20 sold (pending payment). Thanks for looking. Jon

17-70 sold. 10-20 is feeling lonely, wonders why it has been rejected, and wants a new home!