Sean,
iipad Air: I have never had this issue befor upgrading ti 8.0.0. The screen rotate just happens no matter what screen I am on. It dones it when it feels like it. Just a few minutes ago, it did it on my lock screen. The whole screen was upside down. I had to do a full power down to fix it. It has happened on safari also. Sometimes it corrects itself in a few minutes, sometimes I have to re power. I don't use the camera on the iPad much, so not sure if it locks while taking photos. I have also noticed a different problem, while using safari it seems like the Internet stops working even though it indicates that I have a connection. It is like the screen freezes, none of the hyperlinks work. When I upgraded to 8.0.2, all these issues still present.
iPhone6; all of the same issues as the iPad Air. Except that at time when using camera, the camera icon in the camera view will not rotate to the correct perspective. Causing saved photos to appear sideways and upside down.. Powering down usually would solve this, but it would come back when ever it felt like it. 8.0.2 did not fix this.