A lens for the price of a box of fudge and 3 stick of rock?! What a bargain.

Beautiful - Ansel Adams would have struggled to better it. Lovely sharp contrasty B&W image with oodles of depth of field.

Excellent thread topic! I'm with John - JPEG at 14MP and **** quality straight out of the k20d is perfect. Interestingly, I also use the same settings as John in terms of sharpness etc. No real need to shoot raw and personally I cant be bothered with hours and hours of PP on the computer - would far rather spend the time getting the shot right in the first place. Makes me happy to know that I'm not alone and that most forum users seem very happy with JPEGs.

I have the 135-400mm sigma - it is an excellent lens. Image quality superb and the lens is light enough to handhold. I also have the 50-500mm sigma but this is just too heavy to handhold and effectively i can only use it with a monopod so i tend to leave the bigma at home and take the 135-400 when i'm out. The extra 100mm is usually just not worth the effort, although the 50-500mm is weather sealed. I have also used the pentax 80-320 which i was unimpressed with both in terms of image quality and autofocus speed.

the photos show evidence of dust on the sensor. try a rocket blower and failing that the pentax sensor cleaning kit.

I agree with Fatspider - a little dirt on the lens will not affect image quality. See:

http://www.lensrentals.com/news/2008.10.30/front-element-scratches

Much more likely to be dirt on the sensor that's causing marks on your images.

I bought Peter's BG10 and it arrived by RMSD in perfect condition before my cheque had even cleared. Recommended seller!

Thanks everyone! - new manual of photography and photographer's eye now on order. There's a new edition of understanding exposure out later this year so i'll wait for that when it comes out

Can anyone recommend an up to date book on photography? I'm not after a beginners book - I want something which is really detailed. I have a copy of
The Photographer's Handbook by John Hedgecoe which is very good but somewhat dated now? Any thoughts on recent publications????

Absolutely love the thorns photo. Amazing detail. Well spotted image.