There are certain vintage lenses out there that are prone to have glass elements that yellow over time. If you have one of these lenses, you don’t have to live with yellow-tinted results: here’s a 3-minute video in which photographer Mathieu Stern shares a simple trick for restoring the lens.
All you need to do is expose the lens elements to UV light. Stern shows how he placed a yellowed lens in a box on a mirror (to bounce the light around inside the lens) with a UV light pointed down at it. Some people also use some aluminum foil to reflect the light.
After 18 hours of exposure, flipping the lens over once in the middle, Stern was able to get rid of the tint.
Watch the short video above to see Stern’s setup if you’d like to try your own hand at this fix. You’ll just need to pick up a UV light or… take your lens to a tanning salon.