There is a malfunction of the AF on the Dynax 5D in combination with a Tamron lens. Tamron lenses to cause the problem: - Model-A061 AF28-300mm F/3.5-6.3 XR Di Aspherical (IF) - Model-A09 SP AF28-75mm F/2.8 XR Di LD Aspherical (IF) - Model-A05 SP AF17-35mmF/2.8-4 Di LD Aspherical (IF) - Model-A08 SP AF200-500mmF/5-6.3 Di LD (IF) Symptom: AF of the camera body malfunctions (AF coupler runs idly) when the camera is turned off and on again while the access lamp is lit. Supplementary information: - This problem does not occur with the combination of the Dynax 5D with any KM brand AF lens. - This problem does not occur with the combination of the Dynax 7D with the above-mentioned Tamron lenses. - Tamron Japan has released the product information article on this issue via their homepage. (Please have a look at following Site: http://www.tamron.jp/en/news/release/news0928_sweet.html ) The Cause of the problem between DYNAX 5D and above mentioned Tamron lenses: - Tamron lens transmits incorrect signals (information) due to the problem on the lens ROM equipped with the Tamron lens. How to escape the problem: - Make sure that the access lamp is turned off when turning on the camera. - If the AF malfunction occurs, turn off the camera, and turn on the camera after the access lamp is turned off.