Nikon DG-2 lens mount_Mamiya RB A Speed Booster slightly reduces

A Speed Booster slightly reduces the crop of your lenses (from 2x to about 1

but it's not a whole lot bigger than a f1

with a good shutter and smooth focusing

8 "blue dot" lens is in excellent condition

While these screens are compatible with most of the Olympus OM system SLRs

Nikon DG-2 lens mount_Mamiya RB A Speed Booster slightly reducesThe 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.