Had this sent to me via a EOS news letter and thought Id pass on the info:
When the EOS 40D is in AI Servo AF mode, and the
- Sigma APO 120-400mm F4.5-5.6 DG OS HSM or
- Sigma APO 150-500mm F5-6.3 DG OS HSM
Canon-fit lenses are attached with the OS function switched ON, the number of continuous frames per second will decrease.
To overcome this, Sigma is offering a free upgrade service. The problem only affects 120-400mm lenses with a serial number lower than 1011001 and 150-500mm lenses with a serial number lower than 1007001. Later lenses have already had their firmware upgraded.
When the EOS 40D is in AI Servo AF mode, and the
- Sigma APO 120-400mm F4.5-5.6 DG OS HSM or
- Sigma APO 150-500mm F5-6.3 DG OS HSM
Canon-fit lenses are attached with the OS function switched ON, the number of continuous frames per second will decrease.
To overcome this, Sigma is offering a free upgrade service. The problem only affects 120-400mm lenses with a serial number lower than 1011001 and 150-500mm lenses with a serial number lower than 1007001. Later lenses have already had their firmware upgraded.