A SEARious question

Yep, there was an "Auto Sears 55mm f/1.4" version... plus a host of others with the same design, but different casings... released as Auto Rikenon, or Mamiya/Sekor DTL and TL versions (DTL's had slightly closer focusing). Supposedly there was also another one labeled as a "Universon", and the Porst Color Reflex, but I don't have nor have seen any pics of the last two, to know how accurate those might be as lenses made by, or designed by Tomioka.

There was also a Tomioka f/1.8 version released in tandem for Sears and Mamiya DTL (all-black) and TL (Silver nose), plus an additional f/2 for Mamiya TL's.

It would be interesting to know how similar the Tomioka-made lenses for Mamiya, Sears, Ricoh, Porst, Chinon, etc. compare to the Yashica crop.

I've had some of these and the Yashica 50's open to clean the blades, although I've only pulled out entire optical blocks to do it, so I can't offer any insight on equal optical diagrams, part sizes, composition, etc. What I have seen makes it look like the same hands and brain were at work with all of the versions. At the very least, they all render photos that share the same characteristics and IQ. Every one of them are equally sharp, and don't have a lot of sample variation, if at all, for color, contrast, bokeh, CA, right down to a similar OOF transitions across the frame.

Pure conjecture on why Yashica had no equivalent 55mm versions, but there was the entire line of M42 DX, DS, and DS-M lines at 50mm that I would assume were done exclusivly by Tomioka to separate Yashica's offerings on purpose. The coatings may have been different on the DS-M models to elevate them above any of the 55's, and a 5mm difference in focal length at the same speeds may have offered the same or better qualities in much larger batches bound for major production output volumes.

Given that there are 1.7 speeds in the Yashica lineup instead of the 1.8's made in the 55mm lengths, makes me wonder if there could be some advantages with the slightly different focal lengths, but they may have been a bit more costly to make. If that's a possibility, then Sears, et all, may not have wanted a more expensive option in getting multiple speeds to cover a couple of different retail price points. That's not to suggest that there was or wasn't any difference in Yashica's optical diagrams on their 50's versus the 55's... only that Yashica had a habit of wanting the better (or even, costlier) Tomioka versions to carry their brand name.

Obviously Tomioka kept on producing stuff for other brands after they were aquired by Yashica, but it does't seem like anyone minded - only that they got something better that no one else had.