Yashica "S" serial number M42 lenses

Photos of the 4 lenses, in profile and front ring face...




Excuse my forgetfulness in not doing a proper cleanup before shooting them. These and much larger resolution copies of both photos are in a testbed gallery here: testbed.lumiworx.com/#16663105963134 - and it also includes some larger res copied photos of recently listed 'non-S' M42 135mm/13.5cm lenses on eBay, as of last night, 10/19/2022

Just going by eye, it seems there are no difference color-wise in the coatings from the first three. I'm assuming they are Amber HR coating types, but the DS-M has the first rendition of the AR type, plus it has multiple layers. It just occurred to me that I'm doubting if I've ever seen a multi-coated Amber HR lens before - at least on Yashica glass anyway.

As for serial numbers, if the 'S' is dismissed momentarily and it's treated like a name or model qualifier of sorts, there would only be a difference of 7497 units between my DX and 'S' versions if they are sequenced. If some type of sequencing is in play, that would automatically lead me to think the 'S' versions were made prior to the DX series - IF - these are indeed wholly different lens designs internally. My copy of the DS-M has a serial # of 3115192, so that's quite a jump if they continued the sequences based on focal lengths alone. Since the DS-M's don't use the face ring for serials, they don't have any kind of text prefixing of any kind either, and that seems to be the start of the location change for all later lenses too, where they get moved to the base of the outer barrel from that point forward. Not that any of the DS-M series plays into any reasoning on the 'S' lenses... I'm just 'typing out loud'.

My gut is also telling me that the 'S' series are not merely renumbered lenses that might have been serviced and had repair-numbered rings added. There's too many differences in construction (screw locations, aperture ring type, window sizing, etc.), plus the added 5 degree or so focus twist and slightly different scaling marks for DoF sure doesn't seem to jive with it being a standard repair tactic where even the helical was replaced... so I can only think they really are 2 different lenses underneath the skin too, and it's not just cosmetic. That's far too many changes for repaired lenses, and they'd be far cheaper overall to simply replace them with a fresh new lens.

There is another possibility, but it might be far-fetched to think it's likely. They might be more accidental, than planned model releases, and maybe these were a short run of prototypes and eventually (some) went to market. Yashica was making a fundamental change in the move from preset lenses with the Super-R series in their move to 'Auto' pin activated aperture lenses across the entire lens line at every focal length. They may have needed to do some extensive testing of both optical diagram designs and mechanical components, and chose to start out with the usual prime models to hone the process on a select group before expanding them to everything in the catalog.

The Pentamatic move to bayonet mount in my estimation was a good one, but the market blowback was harsh and ended up in a total failure in sales numbers. That was something I'd assume they didn't want any repeat of, and wanted to make sure the next major step was almost bulletproof. They may have gone overboard in producing the next generation of designs, and ended up with excess expenses and a large volume of parts, and they needed to recover some cash while still tweaking the designs. That might have lead them to introduce a new transitional lens series in at least 3 prime focal lengths. I really wouldn't be surprised at this point to see either a 28mm, or a 200mm 'S' lens turn up, but if there are any, I'd suspect they'd be in very small quantities.

There is a very similar conundrum in the world of Fuji lenses. Their best known series of large format lenses are the "W" lenses, but they also sold what appear to be the same lenses marked as "W S" -- which, while not rare, are harder to find. No one has produced any FUJI literature that lists these lenses, and no one has come up with a definitive explanation -- although theories abound, as you might expect. It's possible that the serial numbers might provide a clue, but that might be a needle in a haystack.

I imagine there's a whole other story in how the two lenses that are so close in serial numbers, ended up in two different and distant continents. It also has me wondering if 'S' lenses ended up in every sales region.

I wish there was more transparency too, but someone made a decision early on that not much would get released for public consumption about anything they ever produced. I can understand the rationale of 'trade secrets', but after these mechanical and electronic devices make it to market, it probably doesn't take a lot of time and effort for others to reverse engineer 100% of what the secrets were.

Once upon a time it might have been easier to divine whether something was designed with a certain market in mind. Leica's early rangefinder lenses and accessories were fairly easy to identify in a general sense, with European products marked in Metric, and items bound for the US marked in Imperial values. Unfortunately there's nothing so obvious with a capitalised S appearing in the serial numbers for Yashica's products.

Fuji also had a line of "L" lenses in L39 mount and I suppose those might be similarly distinguished for marketing purposes, but that's not a given as far as I know.

As we both suffer from the same affliction, the associated complications are perfectly understandable.