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03-18-2014, 09:06 AM   #16
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It should be rather easy to tell once you have the lens open. Based on the description of the database of 7 elements in 6 groups, there appears to be only one cemented doublet. Unfortunately, I can't seem to find an optical diagram of the lens on the web or I could tell you exactly which one, and I don't have a sample at the moment I can refer to for reference.

When you open and close the aperture, are the marks in front of or behind the blades? This will at least tell you which group it is you need to remove. On many 50mm 1.2s, the back group is usually much easier to remove than the front, but I haven't opened this model specifically, so I couldn't tell you for sure how easy this one will be to remove.

If you do the light bulb trick, do not use a halogen bulb! It will get much too hot, and you will end up with the top element in the cemented doublet sliding right off! A regular 60 watt incandescant bulb should suffice, and monitor it caredully so it does not get too hot. It will require removing completely the doublet from its cell. and placing directly on the bulb.

QuoteOriginally posted by photoshoper Quote
I'm familiar with opening pentax lenses and have the tools ,, and will try the halogen lamp but the question is which element is affected ,, its not clearly evident
or simply i have to direct the halogen light on the whole lens from back direction ?


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