How to set up sharpness on GoPro Hero3?

Revision PS... I have seen a new video that does demonstrate removing protective plastic rings and twisting the lens 3.5mm. I really felt uncomfortable twisting the lens and didn't want to damage the plastic around the lens. Naturally the video is provided by someone selling replacement lens. I think the below tip may still apply.

After a water dunking I had an internal smudge on the lower left of every picture and video.

When I tore it down I also used another video found on YouTube that appeared to show removing the lens (untwisting) from a mount on the circuit card with a pair of pliers... I attempted that.

After my attempt I don't think the lens is twistable, adjustable or removable from that mount expect for the four corner screws that hold the lens to the sensor. There is quite a bit of padding between the sensor and the lens. I think you might try to see there is a difference between a few turns of the screws that hold the sensor to the lens. There is quite a bit of adjustment between gently snug and tight.

Give that a try. Hope that helps.

Jack Z.