BirdForum is the net's largest birding community dedicated to wild birds and birding, and is absolutely FREE!

Register for an account to take part in lively discussions in the forum, post your pictures in the gallery and more.

Reply to thread

Message: <blockquote data-quote="Red_Shoulder" data-source="post: 3367455" data-attributes="member: 130635">Wow, hard to believe that they did that. Pentax has a great reputation for lenses, too. Would like to try some, st some point, though, anyway,  curious Yes, Aero Ektar sounds right. I guess they used them for surveillance in WWII? Might have gotten some exposure to radiation from them, but might have gotten more radiation from the flight, they say a cross country flight, NY to SF, is 10 millirems, like a chest x-ray. If you are measuring some radiation at 6 inches, that is very radioactive,  more than the check source measured with the CD-V700, which I think is uranium.  But a thread on a photography forum basically said lenses were more radioactive than uranium,  although I think the glass may be more alpha and beta, which is more easily blocked. Not sure on that, though.Wow, I would have thought the Russian stuff would be more radioactive.  I guess they are pretty smart. Interesting,  don't know that I've heard of a 100mm 35mm film lens being radioactive. 70-75% founds about right for older binoculars. When I look at a bright sky in Aculons,  it seems noticably brighter (I don't notice a real difference in birding, though. At least haven't yet.) I think it would take at least a 15% increase to be noticable,  so that's why I think transmission is 90%. Even a 50% increase probably wouldn't be as noticable as you might think. At least, it isn't with flashlights.</blockquote>

Verification