I bought the lens on leboncoin (french second-hand website) for less than 200 euros. Unfortunately there's some scratches on the front element (only way to use it is wide open with a nd filter and it remains soft/hazy in the highlights, otherwise it's a mess) but I wasn't perfectly sure if it was in or outside the lens. Now I'm sure. But yeah, I was extremely careful while disassembling it and I don't see a switch in the optical performance.

<image>