[Daryl]

I do not know if this post should be here and do apologise in advance.

I am always puzzled that the angle between the left arm and clubshaft can be an acute angle and would think this is an optical illusion.

If one were to hold a book in front at eye level, and imagine you are looking at a golfer face on; the bottom horizontal edge is the left arm and the left edge is the clubshaft. Now tilt the book away from you about the bottom edge (left arm) such that the left edge (clubshaft) is on a swingplane of 45deg. The angle between the left arm and shaft is still 90deg, OK. Now rotate the book about the bottom right corner (left shoulder) horizontally say 30deg. The angle between left arm and clubshaft now appears acute to your eyes...optical illusion.

I agree. The camera angle can create illusions and it is sometimes difficult to measure angles from them. Often, many pictures from varying angles are needed to get a better measurement.