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Super Takumar 35mm f3.5
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PostPosted: Mon Mar 03, 2014 3:03 pm    Post subject: Reply with quote

This lens has nothing to do with a Tessar design.
A Tessar has 4 elements in 3 groups. The last group is the only group.
Where did you get this information about the SMC coating which would not apply to the front lens? Don't you confuse with radioctivity due to Thorium on the rear element of some Super Tak.

The information I had is that some Super Tak have already the multicoating without being marketed as SMC: some Super Tak are not single coated. The Tak are single coated.


PostPosted: Wed Mar 05, 2014 11:33 am    Post subject: Reply with quote

memetph wrote:
This lens has nothing to do with a Tessar design.
A Tessar has 4 elements in 3 groups. The last group is the only group.
Where did you get this information about the SMC coating which would not apply to the front lens? Don't you confuse with radioctivity due to Thorium on the rear element of some Super Tak.

The information I had is that some Super Tak have already the multicoating without being marketed as SMC: some Super Tak are not single coated. The Tak are single coated.


First off, as to the design I said it was Tessar-based. If you look at an optical diagram, you will see that this lens is unmistakably a Tessar with the addition of a strong negative element at the front. As to the SMC coating, that comes from Gerjan van Oosten's book (The Ultimate Asahi Pentax Screwmount Guide); he is the expert, and so I would consider his information (which is specific to this lens and this lens only--my suspicion being that the early SMC could not properly coat such a strongly curved element) authoritative.


PostPosted: Wed Mar 05, 2014 1:11 pm    Post subject: Reply with quote

I did not understand that the coating issue was limited to this lens.
About the Tessar design , I have always seen it in relation with 3 elements design the last being replaced by a group ( Novar vs Tessar) . But I am not an optic ingineer.


PostPosted: Wed Oct 01, 2014 6:08 pm    Post subject: Reply with quote

As far as I've heard, think it's from asahiflex on pentaxforums. The SMC 35 has one layer of the modern SMC coating. It looks like it has the modern coating on mine at least, older coatings have another color.