Thanks - I had come across the Eneloop suggestion and had added it to my list of things to try if I was unable to get the camera working with the other batteries - I will bear them in mind for when the current betteries need replacing.

I had this issue with my 2006 *ist DL2 - brand new batteries simply resulted in the flashing empty battery symbol and the camera failing to switch on - tried alkaline, NIMH and Lithium. Strangely, replacing the previous (partially depleted set of batteries) and the camera would switch on fine.

Eventually I decided to leave a set of the brand new lithium batteries in the camera overnight (approx 12 hrs), with the camera switched on and empty battery symbol flashing. The next morning the empty battery symbol was still flashing, however when I switched the camera off and then back on again - HEY PRESTO! The camera switched on and the display showed a full battery symbol.

It appears that a new set of batteries has to be "initialised" in some way. At the moment I know that it appears to require a maximum of 12hrs to do this, so will experiment to determine the minimum amount of time required.

Really glad I got it working - I had also emailed pentax support, but got a response saying that the camera was too old and that parts were no longer available.