Thanks for the links gentlemen.

I'm feeling lucky, I've just picked up some second hand 7x50 Observer C's second hand off the bay.
Well they may not be top of the line Steiners but I've no doubt that middle of the road Steiner's will be more than fine with my middle aged eyes.

My housemate bought some second hand 6x30s and they were bright as bright.
The best optics I've seen since his Schmidt and Bender 6x42 scope.
That encouraged me to get these, but I wanted to see what if any features if any I was missing or if the lenses/coatings would be significantly different.
The Steiner site itself didn't really seem to give much info about the different ranges, so I really appreciate your links gents.

Thanks again.
FireballXL5