[Bagger Lance]

There is a lot to observe in these High Speed Photos.

Notice the Clubface Closing from Impact to Separation?

If the Ball rolled up the face, because of friction, then we should see the ball rise during the compression stage. But the Ball lifts during rebound.

Daryl,

It looks like there is some rolling of the ball on the face during the compression stage. You can see it in the driver and 3 iron photos. Look closely at the logo and ball # and you'll see a slight upward tilting of the ball during compression. Its very, very slight but shows the ball does change its polar axis during impact. Its not just a direct rebound off the clubface from a decending clubhead blow.

This action might explain why sharper grooves help keep the ball in its original axis thereby increasing spin.

Then again, these photos might depict impact after lowpoint.

Just guessing.