Komura 135/2 (Spring 2011)
Even for someone who collects unusual old lenses, this one is something of an oddity. It's a c-mount, branded "Dynamic Optics," and the model name is "Dyotar." Dynamic Optics, of course, is also known as D.O. Industries - a brand that can trace its ancestry back to Elgeet (and Gundlach) of Rochester, New York. "Dyotar" seems to be a name they've used for several different kinds of lenses, including, most recently, low-magnification machine-vision lenses.

But the branding, in this case, masks the lens's true identity. It's a Komura 135/2 preset: a classic Ernostar design. My assumption is that D.O. ordered a small run of these Komuras, customized to their specifications - with a special rear c-mount fitting replacing the Komura Unidapter mount. The D.O. branding is all on the permanently-attached lens hood, replacing the Komura beauty ring. (Alternatively, I suppose, D.O could simply have purchased a batch of Komuras, and done the modifications in-house.) In any case, I've opted to use the Komura name for this set, since I think that will be more helpful in guiding searchers to the images.

I bought the lens in the hope that the Unidapter mount was somewhere underneath the c-mount fitting, thinking that the lens would be too heavy and ungainly to use as a c-mount lens. I was wrong on both counts. The c-mount modification is a permanent one - no Unidapter thread - but the lens is much lighter than it might appear, and it does screw securely into a c-mount->micro-4/3 adapter, so it's perfectly usable as is. The resulting combination would be awkward to handhold, but since I typically use a tripod, I haven't had to confront that problem.

These shots are the result of a test undertaken in suboptimal conditions: bright and high-constrast. This lens's coating seems not to be terribly effective, and it's extremely "glowy" at wider apertures. Wide-open, it's almost a soft-focus lens. The depth of field, naturally, is razor-thin, and the glow around bright objects certainly doesn't help in achieving precise focus. That said, the lens has a very unusual look (including the characteristic Komura golden colors), and it's obviously capable of producing some very distinctive images. I'm eager to see what it'll do in more congenial conditions - and stopped down a bit more.
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