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My favourite ~50mm - Cosinon 55/1.4
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PostPosted: Thu Apr 30, 2015 10:17 pm    Post subject: Reply with quote
memetph wrote:
Distance marking ? Ok watch IR focusing mark . This makes sense.
But feet under/over meters ?

I said that I am not sure about this. I've read this more then 2 times on different sites and it is true for Cosinon and Tominon lenses, which are, for sure, come from Cosina and Tomioka. So it looks like truth. But still...


PostPosted: Fri May 01, 2015 3:17 am    Post subject: Reply with quote
We may never get to the bottom of this..... nor is it really of any importance....

But lets listen to what the man has to say.... he said he did put some time and effort into research ...


1968 - M42 - A/M switch - 8 blades - MDF 50cm - ∅55
Sold it a while ago...




M42 - A/M switch - 6 blades - MDF 35cm - ∅55
Love it, kept it...



PostPosted: Fri May 01, 2015 11:34 am    Post subject: Reply with quote
Well, if f1.2 lens was mentioned already, what would you say about this:



I think we can conclude that at that point Tomioka made glass and Cosina made barrel for this lens. Or there was other third party maker that produced barrels for all these lenses sold under different names. This would explain all the similarities between these lenses.
I think at some point either Tomioka sold the rights for these designs to Cosina (and may be other makers as well) or Cosina really invented its own formulas.

Different mechanics could be explained by evolution of the design, different makers of the barrels or different requirements from the "end" brands.
Different optics also can be explained by the evolution of the design: the very early Mamiya has a convex rear element, there are some Sears and Rikenons with very slightly convex rear element and I am sure there are a lot more internal differences.


PostPosted: Fri May 01, 2015 12:24 pm    Post subject: Reply with quote
dimitrygo wrote:
Well, if f1.2 lens was mentioned already, what would you say about this:



I think we can conclude that at that point Tomioka made glass and Cosina made barrel for this lens. Or there was other third party maker that produced barrels for all these lenses sold under different names. This would explain all the similarities between these lenses.
I think at some point either Tomioka sold the rights for these designs to Cosina (and may be other makers as well) or Cosina really invented its own formulas.

Different mechanics could be explained by evolution of the design, different makers of the barrels or different requirements from the "end" brands.
Different optics also can be explained by the evolution of the design: the very early Mamiya has a convex rear element, there are some Sears and Rikenons with very slightly convex rear element and I am sure there are a lot more internal differences.


That really does throw the cat amongst the pigeons doesn't it.
OH


PostPosted: Fri May 01, 2015 12:47 pm    Post subject: Reply with quote
Oldhand wrote:
That really does throw the cat amongst the pigeons doesn't it.
OH


Smile


PostPosted: Fri May 01, 2015 2:05 pm    Post subject: Reply with quote
There is a simple explanation for it that saves the story coherence: Cosina did not make the body above. Cosina did not make any 1.2/55 M42 lens. It was an early order of one company from another.
See serial of those lenses. COSINON Tomioka only 1000 pieces. Cosina demanded slight adaptation of Tomioka lens outer body look to fit COSINA line of that period.
COSINA of course later developed its own Pentax bayonet 1.2/55mm lens.

Do not forget we just switched from 1.4/55 to 1.2/55. If we add 1.7/55mm we might have to find another supplement explanation.


PostPosted: Fri May 01, 2015 4:55 pm    Post subject: Reply with quote
Pancolart wrote:
There is a simple explanation for it that saves the story coherence: Cosina did not make the body above. Cosina did not make any 1.2/55 M42 lens. It was an early order of one company from another.
See serial of those lenses. COSINON Tomioka only 1000 pieces. Cosina demanded slight adaptation of Tomioka lens outer body look to fit COSINA line of that period.
COSINA of course later developed its own Pentax bayonet 1.2/55mm lens.

Do not forget we just switched from 1.4/55 to 1.2/55. If we add 1.7/55mm we might have to find another supplement explanation.


This explanation can be valid for f1.4 lenses as well, at least for the early all-metal variations.
As for f1.7 lenses - I think we have zero evidences of their relation to Tomioka.


PostPosted: Sat May 02, 2015 8:04 am    Post subject: Reply with quote
dimitrygo wrote:
Pancolart wrote:
There is a simple explanation for it that saves the story coherence: Cosina did not make the body above. Cosina did not make any 1.2/55 M42 lens. It was an early order of one company from another.
See serial of those lenses. COSINON Tomioka only 1000 pieces. Cosina demanded slight adaptation of Tomioka lens outer body look to fit COSINA line of that period.
COSINA of course later developed its own Pentax bayonet 1.2/55mm lens.

Do not forget we just switched from 1.4/55 to 1.2/55. If we add 1.7/55mm we might have to find another supplement explanation.


This explanation can be valid for f1.4 lenses as well, at least for the early all-metal variations.
As for f1.7 lenses - I think we have zero evidences of their relation to Tomioka.


Indeed, solid evidence would only be Tomioka-Chinon signed contract / license of cooperation or Tomioka - Chinon branded 1.7/55mm lens. Funny is, meters / feet principle can also be applied on 1.7/55 M42 lenses.
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