Pentax mechanical problem

[polymoog]

I bought my Pentax *ist DL in June 2006, no idea how many pics I have taken with it by now, probably 50,000 maybe more. I now have a problem with the shutter release button getting stuck halfway down which means the camera is constantly focusing, and I can't access any menus. Turning the camera off and on again, and/or re-mounting the lens doesn't help (and it happens with all 3 of my lenses). If I "tap" on the button it will eventually release again but it is happening more and more (started about 2 weeks, or 3 photo sessions, ago). And the last time it happened (Yesterday), I couldn't get it to release at all ...

I searched around on the internet but only seem to find issues with lenses getting stuck ...

Does anyone else have any experience of this problem, with Pentax or any other camera? Is it possible/worth repairing?

Any info greatly appreciated