I noticed an old post of yours mentioning a Meritar 2.8/50. I just have an old Meritar 2.9/50 and am wondering if it's the same lens. More importantly, I'm trying to figure out the thread size so I can buy a filter/hood. Do you know any good resources for figuring things out about this kind of lens? I don't have any small enough filters lying around to try out, though I suppose I could visit a well-stocked camera store. Thanks for any Meritar wisdom you can impart!