I am wondering if something is wrong with my 5D2. I thought I might have had a bad battery, so I got another one. I got 411 images and have 11% battery life remaining. I hear people boast that they get 600+ easily. Is my battery usage normal?
Are you doing any long exposure shots? That wears down the battery a lot. Live view and HD video also wears it down fast. Do you have the rear LCD turned off when shooting?
I went to an air show and took 950 photos, and probably 10-20 short video clips and still had 25% battery left.