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Forum: Pentax SLR Lens Discussion
12-30-2018, 03:12 AM
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I am still very uncertain:
Of course the serialnumber and the position of the IR mark indicate the 8-element Takumar.
I have 2 of them here with me and I had 2 more in the past because it is a great lens.
But I also had several 7-element Takumars, all of them had this yellow glass.
The protruding is about the glass of the rear element, not the element itself! Both, the 8-element and the 7-element Takumars have the rear element protruding outside of the main body in the same way.
It is the glass itself which protrudes outside, curves in that way, that you would not be able to place the lens (when focused to infinity) on its backside without the glass touching the surface (and getting scratched or marked).
Compare here again: What did I buy? super takumar 50mm 1.4 - PentaxForums.com
The protruding of the glass is not that clear to be seen.
But this extra mentioning of the yellow straw coating is what is by no means typical for the 8-element Takumar, at least for none of the two I have and none of the two I had
previously! Both had absolutly clear glass.
There never was a yellow coating on Takumars but many had radio active glass (thorium-oxide) which tainted yellow over the time and could be "untainted" by placing it into direct sunlight or another constant UV-light. I have many Takumars with this yellow stain, it is the thorium-oxide for sure. There is no yellow coating!
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Forum: Pentax SLR Lens Discussion
12-29-2018, 04:25 AM
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