Hi, I'm hoping someone here can give me a quick idea of what is up with my lens. I'm new to shooting, developing and printing B&W and have been playing around with medium and large format for about a year. My previous experience was with 35mm. I purchased an RB67 not too long ago, and wanted to purchase a 50mm lens for it. I saw one on ebay that looked good (it was described as mint, specifically purchased for one photoshoot) and when I received it, it did indeed look good. I've shot a few rolls, and other than it being slightly soft on occasion (which may be me or may be the lens - at this point I'm not sure I've paid enough attention to the floating element) it looks pretty good. My only question has to do with a "ring" or a "halo" I see when I view the lens at a certain angle. I have no idea what it could be - it doesn't look like separation. To my untrained eye, it looks like the antiglare coating was applied but not to the whole lens. I have attached a photo link. I'm wondering if this is normal-ish and nothing to worry about, or if I should look for another specimen of this lens. Thanks for any input, and I apologize if this isn't the best place to post this. I didn't see a forum to discuss equipment, other than antiques.