Melbobo,
Well the 70-200 f4 isn't really all that heavy. It's much lighter than my 100-400 which I also sometimes walk around with. (That is an arm breaker.) And it's even heavier than my 24-70 which I'm replacing with a 24-105. :)
Ann
I don't know what they are either Melbob. ;-) Saw them when I was out walking in the neighborhood the other day. Of course I had to take their picture. Ann