What spooked this buck?

[deadeye]

He either spotted a doe or one of the big bucks in the area
spotted him.

[Boar]

or the click of the cam maybe

[Onin24Eagle]

The camera spooked him most likely, but not necessarily the "click".  You've probably got it too low on the tree. 

Somebody on this forum, I don't remember who, once posted a link to a youtube video where they studied this by putting a functional camera and then a dummy camera (just a shell, no batteries, nothing) on a tree at a deer's eye level and another camera waaaayyy up above looking straight down at each cam and set to take videos.  What it showed was quite interesting.  Bucks can react very negatively to a camera just being there, whether it's on or not. 

I've tried looking for that video but can't find it right now.  If I manage to locate it I'll put a link here.  It's a good one to watch if you have cameras out.

[Onin24Eagle]

Found it.  Corny13 posted it a while back.  Here it is:

https://www.youtube.com/watch?v=XVQUSR5BdIk&feature=youtu.be