The battery grip does two things:
1) It holds two batteries instead of just one. Doubling your battery capacity. The batter power is always available to the camera.
2) The battery grips also have a few extra controls so that you can hold the camera in a "vertical" orientation (aften referred to as "portrait" orientation) and you get an extra shutter button, main dial, etc. However, those controls will only work if the power switch on the battery grip is switched to the "on" positioon. The controls on your main camera body (not on the grip) should work regardless of whether the battery grip's power switch is on or not (assuming your main camera is switched on.)
Do you lose ability to control the aperture and shutter settings even when using the controls on the main camera when the grip is attached?
Is the switch on the grip in the "on" or "off" position when you have this problem, or does it matter?
Since this is a 3rd party grip, Canon wont be able to do much to support you (other than to suggest you buy the Canon brand grip, which they do support).
Tim Campbell
5D III, 5D IV, 60Da
