Hey there, Recently, I ordered a Panasonic 12-35mm f/2.8 from Amazon Warehouse Deals for 650 pounds. I am planning to use it for video on my GH4. The trouble and ucertainty I am having with this lens is that it rattles inside when I move it around in my hand (not attached to the camera), or when shaken ever so slightly. I am not too sure whether it is the OIS inside, or whether it is simply broken. I have not tested the optical quality yet, as I am waiting for the GH4 to arrive, but I was interested to see if any of you know what this might be. In the hand, it feels as if there is something loose inside, tipping the weight to one or the side when I hold it in my hand and turn it around. This is more prominent if I carefully shake it from side to side, rather than from the bottom to the top. It wasn't a cheap lens so I am a bit worried that they've sent me a defective one. Any ideas what this might be or is it just me being too panicy? Sorry if it has been asnwered before, I didn't find anything! Thanks for any advice!