I was out shooting yesterday, and my polarizing filter fell off the front of the lens and onto the path. Fortunately the glass didn't break, but it did pop out of the filter holder, leaving me with three pieces to reassemble - holder, glass and retaining clip.
My problem is - which side of the filter should be to the front? There are no distinguishing marks, but I believe that (as it's a circular polarizer) the way it goes in is important. So - how do I find out which is the right way round?
