中古 Mamiya Sekor C 180mm F4.5 (内部にほこりと油？)

Bought this used and the glass is surprisingly clean despite the description—just a tiny bit of dust that doesn't affect sharpness at all. Tack-sharp even wide open on my RB67.

Picked this up used for medium format and was pleasantly surprised that the minor internal dust hasn't affected image sharpness at all. Build feel is solid and the focus ring turns smoothly.

Grabbed this as a backup lens and the internal dust didn't affect image quality at all on my test roll—sharp as a tack from wide open. The focus ring turns smoothly, which is the main thing I was worried about with a used piece.