There are more than a couple mounts out there that have a pivot point in them. Stealth Cam makes a good one but I think that it only works on Stealth Cam Cameras. Do a little searching on the internet. You might have a couple bucks wrapped up in them but it would be worth it, imo.

 

I made my own. 1 2" eye bolt course thread that would screw into your board. Need a 2" eye bolt with 1/4"-20 thread which most cameras are threaded 1/4"-20. Then with flat washers (same size as your eye hooks) put bolt thru the eyes with washer and same on the nut side. I carry 2, 1/2"box wrench's with me to adjust the angle and tighten the bolt and nut once you get the angle you want.

As for the 1/4"-20 they come with the nut but I spin the nut off and put on a wing nut and then put on the nut that came with the eye hook. Tighten with a wrench and hand tighten the wing nut against the nut. You might be ok with just the nut, I add the wing nut just to be certain it will not work loose after I have witness tree rats will perch on camera's to eat there acorns etc.

The cost to make bracket $2.75 and I have made several and use them on all my cameras. Now I will advise you one thing. With this type of set up. The camera will be more noticeable vs camera strap to a tree.