Schneider made at least nine (maybe ten, depending on how you count them) versions of the Componon-S 50/2.8. Only the first two had five element formulas, but coatings, optical schemes and diaphragm types have varied in the 42 years this model has been in production. A full guide to identification and serial numbers is at
Delta Lenses. In the case of some lenses it's not straightforward, but the serial numbers tell all.
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Version 1 [10146]: Produced 1975-1981. Five-element, concave-5 aperture. Single-coated.
Version 2 [14849]: Produced 1981-1990. Optically identical to [10146] but with aperture illumination and lever. Single-coated.
Version 3 [Catalogue # unknown]: M25 mount version of [14849]
Version 4a [16828] V1: Produced 1990-1995. New six-element design with concave-5 aperture in BLV-L. Similar appearance to [14849] with crucial minor differences. Lenses produced in 1994 have the same curved-5 diaphragm as [16828] V2, but no green band. Multicoated.
Version 4b [16828] V2: Produced 1995-2008 and beyond. Same six-element design as [16828] V1 but all models have curved-5 diaphragm in BLV-L. Green identifying band. Multicoated.
Version 5 [18827]: M25 mount version of [16828].
Version 6 [14796]: V-mount version of [16828] with Makro Iris body.
Version 7 HM [Catalogue # unknown]: Produced c.1993 in unknown quantities. Likely industrial or high-magnification application.
Version 8 V2 [1097301]: Revised optical design produced from 2020-2021 and marketed as an industrial lens in V38 mount only, but equally suited to enlarger and taking application. Max aperture now f32. All metal body.
Version 9 Pyrite [1097301]: Produced 2021 to date. Rebranded version of V2.