If you stop and think about it, it's pretty difficult to exist in today's world. Vaccines are(n't) out to get your children, there could be Daleks around every corner, and even that vintage lens you scored on eBay might be radioactive, lurking between the sheets, following your every move, wreaking havoc on your DNA when you're not looking. Maybe even stealing your french fries. Or, at least that's what Mathieu Stern was concerned about before he made this video.
If you've ever had concerns about the radioactive coatings used on older lenses, I encourage you to take a minute and watch this video. I have a B.S. in Biology, so I'm pretty much an expert at science, and I can vouch that the experiments that Stern conducts are rock solid and of a high enough quality to be accepted into almost any scientific journal.
From the 1940s to 1970s, a number of camera lenses were manufactured using a thorium coating on the lens elements, rendering the lenses measurably radioactive. Not the smartest idea in hindsight, but probably on about the same risk level as the radiation scare of holding a cell phone up to your ear.
Have you ever bought a piece of camera equipment and been concerned about the materials it was made out of? I'd love to hear your stories below.