So I have been hand holding my 70-200 2.8 and thus the collar was just sitting on my desk...while processing some pictures I had a moment of inspiration as pictured 
(PS crappy picture taken with iphone as I could not be bothered to get the SLR out of the boot of my car to snap this)
(PS crappy picture taken with iphone as I could not be bothered to get the SLR out of the boot of my car to snap this)