Ask someone to hold the camera, then you pull the grip away from the camera and turn the knob counterclockwise simultanneously. You should be able to take the grip off the camera. It's more than likely that the screw of the grip is stripped. Remove ten tiny screws on the grip and lift the cover up. The Phottix BG-5DIII battery grip is a budget-friendly alternative to Canon's BG-E11 battery grip for the EOS 5D Mark III, allowing you to double the battery life and enhance handling when shooting vertical format images. Can it do the same job for less cash, or should you save up for the Canon-branded accessory? Find out in our review. The RRS L-plate is designed to allow the battery magazine to be removed/inserted from the grip while the L-plate is attached. Iām glad RRS included the gap between the vertical side of L-plate and the port side of the body with the BGE11-L. I still have my RRS L-plate for the BG-E6 gripped Canon 5D Mark II and that plate does not have the gap. I am sorry to hear that a "Communication with the right Canon LP-E6 battery is irregular" message appears when using your EOS 5D Mark III with the Canon BG-E11 Battery Grip. Is the right LP-E6 battery in the Battery Grip a genuine Canon battery? You may want to try swapping battery packs in the BG-E11 Battery Grip to see if the message follows .