As I mentioned on my big "Flash" thread - the camera tries hard to balance the ambient light with the flash so it doesn't look too "punched".
The camera doesn't always choose ISO1600 with the flash... only when it's really dark!

EDIT: Try it to see the difference. Try ISO1600 with flash and ISO100 with flash in a normal dimly lit room. You should see a big difference in the result - that's in terms of lighting quality (not IQ).

As I also mentioned, you can set the camera (in Av mode for example) to have the ISO on the front thumb wheel. Then you can override the camera's choice if needed and manually set ISO. You can switch back to Auto by pressing the green button.

Matt

Shoot RAW, Pete Develop with Silkypix
RAW conversion software handling of high ISO noise varies a LOT! Some software produces mush, others, like Silkypix can do an excellent job with a little careful tuning.

I shoot at ISO1600 regularly and get great results. Yes, more noise than at ISO400, but perfectly acceptable. I don't suppose you've ever used high speed film (like the Fuji 1600ASA stuff) and tried scanning it... that's noisy
On the *ist-D I've shot regularly at ISO3200 as well and used Capture One.

TBH you have to acquire a bit of skill at getting the noise control levels just right, but the images are perfectly usable. I have several shots sitting in albums printed at 10x10" that were at ISO1600

If you absolutely have to shoot JPG then software like NeatImage can effectively clean up the noise while keeping the detail - but you would be advised to download the appropriate profile.

For the wedding - shoot RAW

Matt

It's actually quite therapeutic
Whenever I get to wondering if all those magazine and DPreviews are correct, I just pick up his half ton camera bag and try out a 20D with L series glass...
...yeah, it's nice, but the K10D is much nicer

e.g. "You can't quickly change ISO?? No? What a shame!"
e.g. "Wireless flash from the popup? No? Too bad "

LOL!
Matt

Huh?

I have a friend who has a whole pile of Canon gear... I'll try and check it out too
Matt

The ones with live preview do an "Interline Transfer" - they shuffle the CCD data out a line at a time. The rate of shuffling specifies the exposure time.
But interestingly you get other artifacts from this process...
...which you don't get on a "Full Frame" transfer (as DSLRs are - not to be confused with the APS-C vs 35mm frame size). Full Frame transfer devices require a shutter.

But I'm sure there must be other ways of doing it
Matt

Yes

Direct from the K10D manual:
Which is why you duff the camera in if the batteries fail while doing a CCD clean - you mangle the shutter

It's compact digicams that don't have a shutter. The electronics of the CCD is quite different between a digicam and a DSLR (can't remember where I've seen it... something to do with interline CCD... have to dig around )
EDIT: There's some text here: http://photo.net/equipment/digital/basics/ - look under "SIZE MATTERS". Interline Transfer vs Full Frame.

Matt

K10D PEFs open in:
Lightroom, Capture One LE, Silkypix, Photoshop CS2, Bibble, Picasa etc etc.

Are there any more??

BUT you have to have the later versions (or the latest!). For Adobe products you download the "Adobe Camera Raw" update - which is separate from the main product and can also include Adobe's stand alone DNG converter.

Latest version of Silkypix is 3.0.11 (think the K10D was supported from 3.0.9 or even . In fact Silkypix supported the K10D from the time the K10D was launched (not really any surprise there given the links between Pentax and Silkypix!).

Matt

Just to add to this...
The JPG output is compressed and handled in circuit. The PRIME engine has a dedicated JPG conversion circuit that greatly speeds up the JPG. In fact, AFAIK the main CPU doesn't even have to get involved. That's why the K10D can rattle away in JPG mode and still be twiddling its thumbs

On the other hand the compressed PEF format is Huffman encoded (which is completely lossless) and I think has to be handled by the main CPU. As has been mentioned there is some tradeoff between the time to write an uncompressed file vs the time to do the compression.

And to repeat - Huffman encoding is lossless. Completely and utterly. What goes in, comes out - no bits changed at all. Nada. I can point you to the math if you want... but it's brain-ache stuff

Matt

You must have a really "pants" card Pete
I use Sandisk Extreme III and Lexar Pro SD cards (both 133x) and the K10D absolutely flies. Almost immediate replay of images (Under 1 second to view.. histogram shows in another second or so. Scrolling through images is faster than I can see...)
Matt

Because all compressions take serious processor time, and not all compression is the same
Haven't looked at the maths of the DNG, but it probably exceeds the time requirements of the in camera CPU. The PEF compression uses a Huffman tree which ends up being pretty efficient. Canon do a double Huffman compression, and others use different methods. I reckon some of them use custom hardware to do the compression (probably Canon do in their Digic chips).
Matt