The following notice has been placed on the Sigma website:
To our valued customers,
Sigma’s EF-500 DG SUPER and EF-500 DG ST model flashguns for
Pentax mount do not operate with the recently introduced Pentax K100D
D-SLR camera. To overcome this, we will start supplying a free-upgrade
service to our customers.
We regret any problems this may cause our customers who own Pentax
K100D D-SLR cameras and we will take all necessary steps to minimize
inconvenience to these valued customers.
This problem occurs with the Pentax K100D D-SLR camera only.
List of flashguns requiring update for the Pentax K100D D-SLR camera:
EF-500 DG SUPER Pentax fitting
EF-500 DG ST Pentax fitting
The update service is not available for the non-DG version
(EF-500 Super Pentax fitting and EF-500 ST Pentax fitting) of above
To receive the free upgrade, simply post your flashgun with a copy of
your Pentax K100D receipt to;
Sigma Imaging UK Ltd
13 Little Mundells
Welwyn Garden City