Sigma Press Release on Wednesday, October 29th, 2008 (main points)
Notice to customers using Sigma's EO-ETTL II type flashguns.
The following flashguns will need a free firmware upgrade in order to function correctly with the Canon EOS 50D D-SLR camera. This will corect Autozoom and Exposure problems.
EF-530 DG SUPER EO-ETTL II with Serial No lower than 1047200
EF-530 DG ST EO-ETTL II with Serial No lower than 1045700
MACRO EM-140 DG EO-ETTL II with Serial No lower than 2054400
EF-500 DG SUPER EO-ETTL II (see Note 1 below)
EF-500 DG ST EO-ETTL II (see Note 1 below)
Note 1. Firmware upgrade is only possible if the flashgun back panel shows EO-ETTL II marking.
Note 2. This upgrade is not available for flashguns that do not support EO-ETTL II. These flashguns have only EO-ETTL or EO marking on the back of the body.
This free frimware update is available at Sigma Service Centres.
All applicable flashguns shipped after this press release date already have the upgraded firmware.