Nikon DG-2 brand_Voigtlander This is a close-up diopter

This is a close-up diopter lens in a Bay 1 mount

by which I mean it looks exactly identical

It's the kind of lens you'd use if you wanted to take pictures of some Weeping Angels playing soccer

The Industar-61D 55mm f2

Never seen one

Nikon DG-2 brand_Voigtlander This is a close-up diopterThe Nikon DG 2 is a flip up eyepiece magnifier used for precision focusing great for macro or copy work. The DG 2 has 19mm threads, compatible with many Nikon film cameras like the FE and FM; cameras with 22mm or rectangular eyepieces are compatible with the addition of DK 7 or DK 22 adapters, respectively (sold separately). In excellent condition. Eyecup is not included.