I purchased one of these to use with my K20D. Worked fine until I used my Pentax 200mm f2.8 lens with SDM.
Something is incompatible between the SDM and the Metz unit, which resulted in the SDM not functioning correctly (inability to focus) - always needed K20D battery removed to reset.
Since purchased a Pentax flash unit - no problems with the SDM.
If you do not use an SDN lens, it may be fine, but I would still go with a Pentax flash for future compatability.

Goliath,

Many thanks for this piece of info. Had been wondering why my K7 had been taking so long to write to the card. Turned off the distortion correction - all abck to normal.
Thanks again!

For what it's worth, I had a similar with my K20D and 200mm DA* SDM lens. Turned out to be a compatibility issue between camera/len and Metz 36 AF4 flash gun. While the flash is listed as full Pentax compatible, it upset the camera AF system when using an SDM lens.

Removing the battery from the camera for a few minutes restored normal AF operation (without the flash). Purchased a Pentax AF360 and since have not encountered any SDM/AF issues.

I had a similar issue to Colin with my K10D and Sigma 70-300 APO DG.

After much frustration with soft images at 300mm, I took both items to the CR Kennedy (Pentax and Sigma importers) Service department here in Melbourne.

They said that they could 'match' the two items together - a statement that proved 100% correct. Sharp images at 300mm and no adverse effects on my other lenses. All up, including a sensor clean cost was just over $AUD100.00

Surely Pentax service can't be that poor in the UK that problems can onoly be resolved by purchasing new equipment or hacking software settings with dubious East European software?

Sorry, but it seems to me that some people go through a whole of trouble when confronted with focusing issues on K10Ds.

My K10D back-focus issue was resolved by our Pentax Service Centre here in Melbourne for $A100 (55GBP) and included a service check and sensor clean.

Focus is spot-on and I did not have to go through the anguish of hacking firmware etc.

Surely Pentax service cannot be that expensive in the UK to preclude this fix?

As of 28 June, Ted's Camera Store here in Melbourne had 6 K20D bodies (new) at $A899 each. That's about GBP505. Prices vary considerably here in Australia, both from to dealer to dealer, as well as from state to state.