Started this as a cheap way to get fast glass. Ended up with a small box of metal cylinders, a working knowledge of Russian aperture rings, and opinions.

Here’s what I learned paying for it.

Read the seller’s photos, not the seller’s words

“Clean glass” means nothing. Every listing says clean glass. What tells you something is the picture where the seller shines a light through the lens from the back. If they didn’t take that picture, ask for it. If they won’t, move on. There are eleven thousand of these things for sale.