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Was this GAF 50mm f/1.9 made by Tomioka?
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PostPosted: Fri Mar 29, 2024 3:18 am    Post subject: Was this GAF 50mm f/1.9 made by Tomioka? Reply with quote
A GAF 50/1.9 has been listed on my local marketplace. The whole thing looks identical to the early style Auto Chinon 55/1.7 except for the nameplate. This makes me wonder if this GAF 50/1.9 was made by Tomioka. I've seen images of the Tomioka-made GAF 55/1.7 in this style, but never a 50/1.9. I'd like to be enlightened by anyone who's in the know. Thank you! 🙏

Anyone who has a picture of a Tomioka-made 50/1.9 in this cosmetic style, OEM or re-branded, is welcome to post the picture. 👍





PostPosted: Fri Mar 29, 2024 7:10 pm    Post subject: Reply with quote
It definitely is a rebranded Chinon and it came with a rebranded Chinon CS camera, sold as GAF L-CM.
https://www.ebay.co.uk/itm/204680110864?chn=ps&_ul=GB&mkevt=1&mkcid=28
I think some GAF L-CM cameras came with a similar Chinon 50mm f2.0.
https://dehk.wordpress.com/2010/11/17/gaf-chinon-l-cm/

Not to be confused with the later Auto Chinon (and Revuenon) 50mm f1.9 in M42 mount that was a M42 variant of the contemporary PK mount lens, to be sold at the '80s very tail end of the M42 era, as the kit lens for the Chinon CS-4 (and Revue SD1).

There is no strong evidence that the Chinon 55mm f1.7 M42 lens and its rebranded variants (including GAF) were actually manufactured by Tomioka. As far as I know there is no Chinon Tomioka branded 55mm f1.7, but there are 55mm f1.2 and some early 55mm f1.4.


PostPosted: Sat Mar 30, 2024 8:46 am    Post subject: Reply with quote
iso rivolta wrote:
It definitely is a rebranded Chinon and it came with a rebranded Chinon CS camera, sold as GAF L-CM.
https://www.ebay.co.uk/itm/204680110864?chn=ps&_ul=GB&mkevt=1&mkcid=28
I think some GAF L-CM cameras came with a similar Chinon 50mm f2.0.
https://dehk.wordpress.com/2010/11/17/gaf-chinon-l-cm/

Not to be confused with the later Auto Chinon (and Revuenon) 50mm f1.9 in M42 mount that was a M42 variant of the contemporary PK mount lens, to be sold at the '80s very tail end of the M42 era, as the kit lens for the Chinon CS-4 (and Revue SD1).

There is no strong evidence that the Chinon 55mm f1.7 M42 lens and its rebranded variants (including GAF) were actually manufactured by Tomioka. As far as I know there is no Chinon Tomioka branded 55mm f1.7, but there are 55mm f1.2 and some early 55mm f1.4.


Thank you very much, ISO, for chiming in. 🙏
The GAF L-CM cameras in the two links you provided sure are interesting as they sport a Chinon 50/1.9 and 50/2 respectively lens instead of GAF ones although the lenses are the same except for the nameplates.

Indeed there are no Chinon Tomioka double-branded 55/1.7 in existence. However, I found a Japanese site whose owner, a lens repairer, lists the Chinon 55/1.7 as manufactured by Tomioka from his experience of repairing both Chinon and Tominon lenses. Check out the lens' detailed blog articles (Google Chrome's Translation function helps a lot). Quite fascinating reads:
https://pakira3.sakura.ne.jp/wp/?page_id=80921


PostPosted: Sat Mar 30, 2024 4:13 pm    Post subject: Reply with quote
I don't find his reasoning convincing at all, and here's why: The supposition that various vintage primes, especially Chinons, are "Tomiokas" by and large comes from "transitive creep" from the handful of early leather gripped 55mmm f/1.4s by Chinon that actually says "Tomioka" on the name ring, and to a lesser extent the 21/3.5 and 55/1.2.

There are many 55mm f/1.4 lenses out there from many brands (Chinons without "Tomioka" on the ring, Rikenon, Mamiya, Cosinon, etc) that have lens elements with the same physical dimensions, so they are presumed to have been manufactured by the same foundry, i.e., Tomioka. I'm more or less willing to buy the contention on its face that the glass for these was supplied by the Tomioka foundry. But here's the thing: if you look at these various lenses, other than among straight rebrands, the mechanical and exterior construction on them varies pretty widely. This even includes simple things like internal retaining ring design. And they all use different coatings. What this says to me that Tomioka was likely only involved in supplying the optics, and that coatings, mechanics, and styling were handled by the lens manufacturers.

If this is the case, then so what if a Chinon 55mm f/1.7 has similar styling construction to the f/1.4? I'd expect that to be the case from two lenses from the same manufacturer, regardless of whose optics they used, and they really could have come from anywhere. Indeed, if you move on to the later Chinon lenses, you can find versions of the 55/1.4 that are styled and constructed similarly to ones that say "made in Korea," right on them, which certainly aren't Tomioka-made lenses. And no, the click stop and aperture mechanicsms are not "unique" to Tomioka lenses as this guy claims, or even out of the ordinary, in any way. They are bog standard designs employed by a number of Japanese manufacturers.

In sum, there is no inherent link between exterior styling or interior mechanics of these lenses and who supplied the optics. And, oh, the styling and mechanicals of similarly-specced lenses by Yashica, who actually owned Tomioka through the period all of these lenses were made? Completely different from the type this guy lists as diagnostic of a lens being a Tomioka!

So why exactly, then, if the mechanicals/appearance are not actually diagnostic, then why exactly do many still assume a leather grip on the earlier lenses = "Tomioka?" The 35m f/2.8, 55mm f/1.7, and 135mm f/2.8 all had leather grips but never said Tomioka on the ring, even when some of the higher end lenses actually did? IMO, it's more likely none of them ever were Tomioka-designed or built. In the end, who cares? Why fetishize the name of a company that may or may not have made the lens when the Internet has made it dead-simple to evaluate the performance of a lens through numerous examples.

The guy in the link sells these lenses through Yahoo auctions. It says it right at the top of the page. And he makes more money for a listing labeled Tomioka. There's his incentive. Deosn't make him right or credible.

[quote="Sakyaputta"]
iso rivolta wrote:

Indeed there are no Chinon Tomioka double-branded 55/1.7 in existence. However, I found a Japanese site whose owner, a lens repairer, lists the Chinon 55/1.7 as manufactured by Tomioka from his experience of repairing both Chinon and Tominon lenses. Check out the lens' detailed blog articles (Google Chrome's Translation function helps a lot). Quite fascinating reads:
https://pakira3.sakura.ne.jp/wp/?page_id=80921


PostPosted: Sat Mar 30, 2024 4:57 pm    Post subject: Reply with quote
BrianSVP wrote:
I don't find his reasoning convincing at all, and here's why: .....


Thank you very much for sharing your insightful reasoning, Brian. You have an excellent sense of logic! 👍 And I find your inference of Tomioka only supplying the optics quite feasible. I've just begun to be interested in the Chinon and Tomioka stories very recently, so I really don't have a set point of view or opinion, and welcome anyone who can enlighten me on the subject.

Indeed, at the end of the day, it's the optical performance, feel in handling, and even the look of a lens that matters to the user. Brand names are only letters engraved on the nameplate.

However, it's still fun to learn the stories through discussion and research. It never hurts to know more of the truth, IMHO.


PostPosted: Sat Mar 30, 2024 8:49 pm    Post subject: Reply with quote
BrianSVP wrote:


There are many 55mm f/1.4 lenses out there from many brands (Chinons without "Tomioka" on the ring, Rikenon, Mamiya, Cosinon, etc) that have lens elements with the same physical dimensions, so they are presumed to have been manufactured by the same foundry, i.e., Tomioka. I'm more or less willing to buy the contention on its face that the glass for these was supplied by the Tomioka foundry. But here's the thing: if you look at these various lenses, other than among straight rebrands, the mechanical and exterior construction on them varies pretty widely. This even includes simple things like internal retaining ring design. And they all use different coatings. What this says to me that Tomioka was likely only involved in supplying the optics, and that coatings, mechanics, and styling were handled by the lens manufacturers.



I'm not even sure the optics were sourced from the same place. I don't have all versions of the group of lenses said to have a single source, but I do have enough to say that they most likely are not from a single source, or at the least, not from a single design. My conclusion comes from a recent effort to catalog the photographic items in my possession, and as part of it I used a radiation detector to take readings at the front and rear of each lens. Readings as follows (uSv/hr) (Front, Rear)(anything below 0.2 is effectively 0, indistinguishable from background levels.)

Chinon (M42)(Tomioka marked, serial 309060) 0.09,0.09
Chinon (M42)(not Tomioka marked, serial 500591) 0.11,0.12
Cosina Cosinon (M42)(serial No.100644) 0.14,0.12
Exaktar (Exakta Real Mount)(Cosina)(serial No.086455) 0.11,0.12
Exaktar (M42)(Sankor)(serial No.140560E) 0.12,0.17
Mamiya Sekor (M42)(DTL black version)(serial No.120413) 1.04,1.70
Mamiya Sekor (ES Mount)(Serial No.16823) 0.13,0.16
Rexatar (M42)(Maker unknown, suspect Sun Optical)(Serial 720061) 4.41,1.14
Rikenon (M42)(Maker unknown)(Serial 51649) 5.13,10.36
Sears / Sekor SX (M42)(Serial 34502) 0.12,0.23

So the glass mixes used don't appear to be the same between all lenses, nor even between the ones that had detectable levels of radiation. The Mamiya DTL lens is probably the earliest there, from around 1966. So for the theory to be correct they started with radioactive glass, then used non-radioactive for Tomioka marked lenses, then dipped in and out of Radioactive mixes at random in the years following. I find the idea of different designers coming up with their own slightly different designs (remember most designs for F2 and faster lenses were broadly similar to their peers, with generally only a few basic variations of layout) more believable than the idea that they all came from the same place. Much is made of the flat back element, many 55/1.4 lenses shared the same feature, including the Petri lens and the earlier Rikenon lens for the Nikkorex F derived Singlex, both of which are clearly different designs, but still had that feature.

I also find the idea that they were slavish copies of Zeiss designs similarly poorly thought out. Both ideas are somewhat dismissive of the intellectual potential held by the Japanese industry at that point, which is really not an accurate view of how it was.


PostPosted: Sat Mar 30, 2024 10:49 pm    Post subject: Reply with quote
I totally agree with Brian and I don't think it's Tomioka. I am inclined to believe that GAF = Cosina


PostPosted: Fri Apr 05, 2024 3:46 pm    Post subject: Reply with quote
Interesting. And what does GAF stand for please?


PostPosted: Fri Apr 05, 2024 4:04 pm    Post subject: Reply with quote
Phalbert wrote:
Interesting. And what does GAF stand for please?


General Aniline & Film


PostPosted: Sat Apr 06, 2024 7:34 pm    Post subject: Reply with quote
successor to Agfa after the war

p.


PostPosted: Mon Apr 08, 2024 8:03 am    Post subject: Reply with quote
BrianSVP wrote:
Phalbert wrote:
Interesting. And what does GAF stand for please?


General Aniline & Film


👍


PostPosted: Tue Apr 23, 2024 1:48 am    Post subject: Reply with quote
Alun Thomas wrote:


Rikenon (M42)(Maker unknown)(Serial 51649) 5.13,10.36 front, rear uSV/hr





I came across more information today that muddies (or clears) the water on the subject of the 55/1.4 lenses. I bought the black camera and lens on the left recently, the price was quite good, even though I already owned a copy (the right hand lens). The right hand camera and lens were obtained separately, so may be from slightly different time periods to each other. The newer lens with a higher serial number is not detectably radioactive from either the front or rear, but is almost identical to the older one that is quite strongly radioactive (for a lens). The coatings have a slightly bluer colour, that's the only other visible difference. So, maybe the same manufacturer did dip in and out of radioactive glass mixes, or at least start with radioactive types and then move to non-radioactive types. There are other possible explanations, they could have changed supplier, that seems much less likely though.


PostPosted: Tue Apr 23, 2024 2:40 am    Post subject: Reply with quote
Is that browning I see? Smile

Asahi went through similar glass changes. Can you date these? I'm thinking an industry trend can be dated if the periods correlate.

The lens calculations are likely different, as are the Asahi lens' calculations, as evidenced by different front element diopter. Can you measure the diopter of the Rikenon front elements to compare?


PostPosted: Tue Apr 23, 2024 9:01 pm    Post subject: Reply with quote
The right hand lens has browned slightly, it's hard to pickup as the coating is amber as well, but if shining a white light source through both lenses, the light emerging through the right hand lens has a yellow/brown hue. I don't have any equipment for measuring either the curvature or diopter. They look identical to the naked eye.


PostPosted: Tue Apr 23, 2024 9:53 pm    Post subject: Reply with quote
Exposure to light can clear the browning, as you know.

Lens Clock
Click here to see on Ebay


PostPosted: Wed Apr 24, 2024 5:26 am    Post subject: Reply with quote
I presume it is the UV component thatwill knock about the errant glass components-

However MC-coatings and many glass types are notorious for blocking UV, so success (if daylight or UV lamps and not ordibnary low colour temperature bulbs are used) is most likely limited to the front and rear elements-

p.
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