I have a canon 5d mark 3. After some evening shoot i took a break and continue shooting some more pictures in AV mode. This time the preview in the live view is blown out almost completely white. I switch to manual mode and the exposure in the live view is correct. What's going on here? I want to shoot in AV mode. Here's the setup.
Canon 5D Mark III
Canon 24-70L 2.8

