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03-05-2021, 07:25 AM   #1
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Combining tak 50/1.4 8el+7el

The scheme of the lens is the same so why not take what is the best from s-m-c (front) with what’s the best in 8el?

Creating Super-Super Takumar 50/1.4

03-05-2021, 08:03 AM   #2
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How is the scheme the same when one has 8 elements and the other has 7?


03-05-2021, 08:17 AM   #3
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See those three elements that are together? In practice these had to be glued together in a very precise manner. This was time consuming and drove up production costs, Asahi Optical Company did not keep it up for long. Having proved that they could outdo Zeiss, they quietly went over to the seven element design.
03-05-2021, 09:14 AM   #4
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Threads are not compatible

03-05-2021, 11:45 AM - 1 Like   #5
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These things are too valuable to create Frankenstein monsters with...
03-05-2021, 01:35 PM   #6
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Yeah I just don’t see why you’d bother... both are great lenses and the risk would be pretty great that you’d mess both of them up, and the cost to do it would get you one of the nicer current lenses in the stable.
03-05-2021, 01:44 PM   #7
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I have only 8el but I would love to change elements one by one besides the extra one. 1 rear, 3 front look the same
03-05-2021, 02:37 PM   #8
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QuoteOriginally posted by googlarz Quote
I would love to change elements one by one besides the extra one. 1 rear, 3 front look the same
If you believe the urban myths, there were some 'hybrid' 8 and 7 element lenses produced during the transition. Leaving aside possible differences in lettering or A/M switches used, the only pics of claimed 'hybrids' that I have seen simply have the aperture and IR marks transposed by repainting. The idea of switching elements is simply not feasible. As you say, "1 rear, 3 front look the same". If they are then switching them could have no effect. But optical science is just that - a science. There are not bins of lens elements that designers play with to see what they will get. They design the elements to get the lens they want and some of the small tweaks to an element may not be apparent to the eye. Just because two elements look the same, does not mean that they are. If you wanted to conduct an experiment by switching elements (if that is possible) and documenting the changes in image quality for each switch, then I suppose some people may find the result interesting. But I am not sure that the results would be worth the effort.

03-05-2021, 02:56 PM   #9
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QuoteOriginally posted by googlarz Quote
I have only 8el but I would love to change elements one by one besides the extra one. 1 rear, 3 front look the same
I've heard it said more than once, that those optical formula drawings are more of an estimate than exact representations. Even if they look the same there might still be a bit of a difference in regards of the shape - even a difference that you can't see might still make the lens perform differently - and you don't know the materials used in each element. Swapping a radioactive thorium element into the 8-element design, for example, would have quite unpredictable results... and even for regular glass there's different formulations as well.

But if it's easy enough to swap back if it doesn't work well, why not try if you have the lenses and the skills...
03-05-2021, 03:07 PM   #10
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QuoteOriginally posted by Not a Number Quote
How is the scheme the same when one has 8 elements and the other has 7?
They are both broadly Planar?

QuoteOriginally posted by ChristianRock Quote
Swapping a radioactive thorium element into the 8-element design, for example, would have quite unpredictable results... and even for regular glass there's different formulations as well.
The thoriated element in the SMC version is second from the rear and would not be included in the proposed Frankenlens. My opinion is that if the OP wishes to risk trashing an 8-element ST or an otherwise good 7-element SMC, it is their business, but there will likely be widespread shaming by Tak enthusiasts on this site.



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03-05-2021, 04:48 PM   #11
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Takumars were not really built with 100% interchangeable parts. You can see differences in common lenses that should be identical. Also some differences in domestic vs. export lenses, like screw type. It looks to me like there was a lot of hand work involved. I wouldn't expect success.
03-05-2021, 04:57 PM   #12
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I'm curious how the thread starter determined that "the front is the best part" of the SMC 7-element lens. It is an entire, singular device, and cannot be separated as such.

The 8-element Takumar was considered the better performer both then and now. I wouldn't feel at all bad owning either (assuming I wanted such a lens). It is going to be an extremely rare hobbyist that can somehow jumble together the elements from two different lenses and come out with a device that is functionally superior to either of the devices they started with.
03-05-2021, 06:20 PM   #13
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QuoteOriginally posted by pres589 Quote
I'm curious how the thread starter determined that "the front is the best part" of the SMC 7-element lens.
I suspect there is the assumption that coatings are more important in the front groupings.


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03-07-2021, 12:38 PM   #14
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So maybe the last element from the s-m-c? Why not? So many people say it’s not the same - did you tried it?
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