Greetings Analiese,
If possible, let's test a different lens with your EOS 5D Mark II camera which will help us determine if there may be an issue with the auto focusing system on the camera. With the other lens, let's try using one of the other focus points aside from the center focus point to see if the same issue occurs. We would recommend testing this in a well-lit environment or possibly outside during the daytime when there is a lot of light available.
Prior to testing, I would also suggest removing any lens filter that may be attached to the front of the lens since certain lens filters may sometimes interfere with the camera's auto focusing system.
On the EOS 5D Mark II camera, let's also check the auto focus when shooting through the Live View option which is where we would use the rear LCD screen for taking picture instead of the viewfinder. This is due to the Live View mode using a different type of focusing system. If focusing with Live View seems to work well, then it may be an issue with the camera's auto focusing system through the viewfinder.
Unfortunately, this camera model has reached the end of its service life and cannot be sent to our facility for repair. An alternative option may be the Canon Upgrade Program.
The Canon Upgrade Program option allows you to replace your current camera with a new or refurbished Canon camera at a discounted price. If you would like to take part in the Canon Upgrade Program, please call our Sales Department at 1-866-443-8002 from Monday - Saturday between 9:00 am to 9:00 pm ET. Be sure to have your serial number for your camera available at the time of your call.
