Strange lens/shutter noise?

[mj4456]

Whilst messing about trying to get a macro shot (for another forum thread) I could hear a noise from the lens/body, it sounded like the shutter had a slight stutter/machine gun action (about 3 per second)after the shutter operated, to stop it I had to switch the main switch off. It wasn't quite as loud as a normal shutter operation and the camera would do nothing else whilst this was happening, set lens back to normal and tried a couple of shots then back to macro and was ok. Body is an eos1 mk1 and lens is sigma 28-135, battery was low, any ideas.?

 

[Frobius]

Have you been able to replicate it with a new battery on? Might be something there?