I just received my 60mm macro. Boy is it small. But I have a question. On the side of the lens is a button which can be rotated from 0.4 mm to infinity, .19mm to infinity and .19 to 0.4m then the final is 1:1. The problem is when I try to go to 1:1 it does not click in rather it snaps back to .19 to 0.4m. I am wondering this is normal or a problem with the lens and I should return it?