I don't think modern cameras are going to open/close the shutter continuously. That would cause a lot of noise while filming, and they usually record sound too.

I don't think modern cameras are going to open/close the shutter continuously. That would cause a lot of noise while filming, and they usually record sound too. They rather use "electronic shutter" while filming, which is just another name for ignoring some exposure time. So it would count as one click, or maybe less. > can you completely avoid using a battery with a power line adapter? This is going to depend on the particular camera. I just tested a mirrorless camera, doesn't work without a battery, and doesn't use the DC power while on.