So, this is something I've noticed for a long time and have just assumed that it represents superior glass from its craft and polish or some sort of coating.
Let me try to explain what I'm referring to...
When looking through a lineup a different scopes I've noticed that when checking for eye relief and forgiveness that some do not immediately go to black the mm you are off center... Instead I see what looks like a polished outer ring, a swirl, that as you continue to move off center fades to black. When I say 'outer' I mean a very thin, narrow ring, but still quite noticeable. The only reasoning I could come up with myself is that possibly this is from a lens that is polished or slightly rounded near its outer edge...? Maybe that would cause this somewhat prism like effect? Honestly I really don't know but would like to hear if someone knows why this happens?
**** Edit: Answered, scroll down to hear explanation from Zeiss' Customer service.
Let me try to explain what I'm referring to...
When looking through a lineup a different scopes I've noticed that when checking for eye relief and forgiveness that some do not immediately go to black the mm you are off center... Instead I see what looks like a polished outer ring, a swirl, that as you continue to move off center fades to black. When I say 'outer' I mean a very thin, narrow ring, but still quite noticeable. The only reasoning I could come up with myself is that possibly this is from a lens that is polished or slightly rounded near its outer edge...? Maybe that would cause this somewhat prism like effect? Honestly I really don't know but would like to hear if someone knows why this happens?
**** Edit: Answered, scroll down to hear explanation from Zeiss' Customer service.