My Phantom 3 has been rock solid, when I hover at 6 or 7 feet (really at any height). Today, I took it out and had it do an auto take off, and it hovers, in a circle... ? Its is still facing forward, but instead of staying one place, it is doing a 2 or 3 foot diameter circle. The only thing I can think is that I put on a polar pro polarized lens. Could this few extra grams of weight cause this to happen? I have never heard of anyone else having an issue after adding the lens? Next step is going to be to do another IMU calibration (I had just done this yesterday, but with the stock lens). Hopefully I am not going to have to do an IMU calibration every time I switch lenses? Thought, suggestions?