34 years of Pentax 15mm Lenses

Today I took delivery of an SMC Takumar 15mm f3.5 which I won on eBay. This lens from 1975 features an aspherical element - a rarity back then. Supposedly Zeiss collaborated with Pentax in its design. You have to see it to believe it - the front element is huge and very steeply curved. It can only use internal filters because of this massive front element

This is my fourth Pentax 15mm lens - I also have the 15/3.5 K and A versions which share the same general design as the SMC Tak, but without the aspherical element, as well as the DA15/4 Limited, which is only a fraction of the size and weight of the older versions.

Surprisingly (to me, at least), its sharpness is in the same ballpark as my much more modern DA15/4, at least in the center of the image. Not surprisingly, it is lower in contrast, weaker in the corners, and has greater distortion. But it is the sharpest of my three older 15s, perhaps due to its aspherical element.

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Jim King - Retired Colormonger - Suburban Detroit, Michigan, USA; GMT -5h (EST)
Pentaxian for over 50 years.
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A fanatic is one who can't change his mind and won't change the subject.
- Sir Winston Churchill
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The difference between genius and stupidity is that genius has its limits.
- Albert Einstein