PT5605. Prototype lens, released by FED since 1937. For reproduction purposes. Focal length - 5 cm (5.2 cm), aperture range f3.5 - f18. Focusing range from 0.15 m to infinity. Number of elements/groups: 4/3.  Angular field - 46º. An ultra rare to find nowadays. Fed (M39) mount. Lens opposite from private collection in Russia.
	PT5605 - Fed Macro prototype lens.
PT5610. Another prototype version of the particular lens. Slightly different body finish with wide brown plastic ring on the top. Photos courtesy of  LeicaShop (Austria).
	PT5610 - Fed Macro prototype lens.
PT5615. 1st version of regular Fed Macro Macro lens. Signally changed body design. Very uncommon to find nowadays. Lens opposite from private collection in Russia.
	PT5615 - Fed Macro lens.
PT5620. Lens identical to PT5615 with few exceptions: engravings "Расстояние от объекта" ("distance from object") replaced by single "P" and  engravings "Масштаб" ("Scale") replaced by single "M". Less natty screwed bolts. Some lenses have no serial number on the rear side. No otherwise different.
	PT5620 - Fed Macro lens.
PT5630. Next generation of the FED Macro lens. lens identical to regular Fed 3.5/50mm, but with additional scale on the metering scale disk. Not common to find nowadays.
	PT5630 - Fed Macro  #8748.