The SMC-FA 24-90 has colour, sharpness, and contrast that are superb. And it's the bokeh that's just superb.
Some find the range not too useful (as it's not wide enough), but for me with the SMC-DA 12-24 they make a great pair! I particularly like the 24-90 for portraits.
Occasionally they come up at silly money - probably around £150. Not bad as it was nearer £400 when new!
Matt

EDIT: The 24-90 performs very well indeed on the K20D. A small amount of CA - but easily fixed in Silkypix

Thanks Terry & Clarky
The K20D has given me a new burst of photographic enthusiasm!
Matt

I like it a lot The CMOS sensor seems different when processing RAW - seems smoother and with a larger latitude.
My last 3 ephotozine shots are K20D:
http://www.ephotozine.com/u16488#photos
(Horse Whisperer, Backlit Roxy, and Light Up the Darkness)
The resolution is just phenomenal - even on the (now ancient) SMC-FA 24-90 that is really shining!
Even ISO3200 is incredibly usable - not in all circumstances - but quite astonishing really. May post up a shot taken with the 50mm f/1.4 (ISO3200, f/2.2 IIRC).

There have been a few subtle improvements too along the way in the K20D...
It'll be pushed at the weekend - I'm doing a favour for some good friends and doing their wedding That'll be a blast
Matt

Thought I'd provide some links to other Pentax-related gear:

Metz 15 MS-1 Wireless Ring Flash

Sigma 4.5mm and 10mm lenses for Pentax

Sigma EM-140 Ring Flash

Looks like there'll soon be plenty of ring flash options
Matt

Well done
(I haven't been keeping up with the Pentax gallery - nice to look through it!)
Matt

Are you volunteering Don?

Terry - either JPG or RAW, but better in RAW
Matt

Just cleaned the K10D. If you wipe harder and move the sensor, then even with SR off the mechanism still pulls it back into place.
Don't forget that the CCD is held in place only by magnets
Matt

EDIT: You'll never get rid of 100% dust. You just get better at spotting it and cloning it out

It'll be a while... up to 12 pages and I haven't even started!!
And then I'll need images too...
Matt

Terry,
You have the choice. Lightroom can handle PEF. If anything can't then Adobe's standalone converter will turn it into DNG.
Matt

Can you provide EXIF information? (Aperture, ISO) and an idea of the distance?
(Sounds like you're asking the flash to compete with a humongous burning nuclear ball )
Matt