Hey there
I installed the 8.1 preview over a fully functional 8.0 installation and I found out that the windows camera app does not recognize the Logitech Webcam Pro 9000 anymore(used to work fine before the upgrade).
I have to add that the camera drivers are properly updated and the camera works just fine in Skype / other applications, so the problem is only within the default windows camera app. Is it something that will be fixed by a future build?