K10 -underexposes with TTL

Hi All, I have a Jessops 360AFDP gun. When i use in TTL mode with my K10D it seems to give approx 2 stops underexposure with the camera in any auto mode (even when the subject is only a couple of metres away). This seems true for bounce and direct flash. I'm sure I've read the various manuals which make it all sound idiot proof. The gun knows its in TTL mode and seems to pick up the lens focal length.

Anyone got any thoughts?

Are you sure it's TTL and not P-TTL?
I believe that the Jessops flash doesn't support P-TTL and I know for sure that the K10D doesn't support TTL only P-TTL.

About the P-TTL and Pentax it seems that the only camera that expose correctly is the K-7 all others have around 1 stop underexposure with P-TTL. The solution around this is to set the flash output in the camera +1 EV.

Thanks for the comment. I'll certainly use the exposure compensation option as it will be more versatile than having to work in full manual control.

As for P-TTL vs TTL -the TTL is what the gun reports on its lcd screen but as far I I understood the Jessops gun is menat to eb suitable for the K10D (or have I been mis-informed by the store?)

I have no personal experience of the Jessops flash but as far as I know, none of them is P-TTL capable, they are TTL flashes.

The only Pentax DSLR's that are TTL (and P-TTL) enabled are the *istD and *istDS.

None of the newer Pentax DSLR's (including the K10D and K20D) supports TTL flash metering, only P-TTL.

If you were told by the store that a TTL only flash would be fully compatible with a K10D, you were misinformed. All third party Pentax dedicated flashes can of course be used in manual mode, including Jessops products.

As I was brought up on manual flash I guess I'll cope! Its frustrating that the Jessops guys couldnt have told me that the K10D they'd sold me wouldnt work in auto mode with the gun I later went in to buy from them.

They were told it was for the K10D....mmmm

These days I use SRS as a supplier -I wish I had known of them before!

Thanks guys for your honest comments. This forum is a great place!

If I use a AF-540 as a wireless slave to my K10d with the built-in flash
set as controller, I suppose the compensation will affect the remote flash gun.

But what if I set the built-in flash as master, would that compensation affect both or just the built-in (or just the remote) ?

Thanks
Ragnar

They probably hadn't a clue. How old was the shop assistant who served you? 17? 18 maybe?

Nuff said.