Sigma has apologised for an error affecting some of its lenses and the Canon 40D.

The company has released a notice to all Canons 40D owners about two of its lenses offering an update service to fix know bugs and issues.

According to Sigma, some lens owners will notice issues the number of continuous frames per second decreasing.

The problem won’t affect all Sigma lenses however, just the APO 120-400mm F4.5-5.6 DG OS HSM for Canon or APO 150-500mm F5-6.3 DG OS HSM for Canon and when shooting in AI Servo AF mode.

Sigma has said that the company plans to start supplying a free-upgrade service to our customers from today.

List of lenses requiring update for 40D camera:

APO 120-400mm F4.5-5.6 DG OS HSM for Canon Serial Number lower than 1011001
APO 150-500mm F5-6.3 DG OS HSM for Canon Serial Number lower than 1007001