Super-Komura 90-250/4.5 Uni-Auto M42 mount

luisalegria · Expire: 2018-01-18

I picked this lens up very cheap as it has a small scratch on the front element and the lens mount was very loose. A little work with a screwdriver and alls well.

I think this lens came out around 1970. This is a very handsome devil, a striking and stylish design up there with the contemporary Yashinon-DX series and the Tamron Adaptamatics. That was the high point of lens aesthetics I think.

Mostly its quite a conventional two-touch zoom of the time. It has the curious star-shaped iris that Komura was so fond of, but I couldn't get any interesting highlights from it.

It has the second (of three I think) styles of Komura interchangable mount systems, the Uni-Auto (the earlier Unidapter was a sort of T4-type for presets). The same idea as the Adaptall or T4, this one was based on a bayonet. Line up the circles and turn until it locks. To unlock, hold down the latch button and turn the other way. This one is simpler than either Adaptall or T4, and seems less fiddly. Of course, there is no way to provide for open-aperture metering.

Its a fairly small lens for the focal range, certainly in those days. Its much smaller and lighter than the equivalent Tamron Adaptamatic 80-250, the early Sigma 75-230 (often seen as Yashinon-R's),the Tokina-made 75-260/4.5, etc. Its slightly longer than the Tokina 90-230/4.5, but no heavier. Its not only constant aperture, but it holds focus very accurately while zooming, which is not true of most of the competition. It also focuses quite close for the type, 6ft/2m. In its time it must have been quite a contender. Komura was a small company with negligible marketing though.

Problems, it has a couple. The rear element protrudes, which always makes me nervous, and the front barrel rotates to focus, and mine is very loose, so even though its a two-touch, it creeps.

Performance is very good for what it is. It is sharp at 4.5, though there is a touch of softness in the right light, mostly at 250mm. Its as sharp as I can make out on my sensor at 5.6. Contrast is excellent. There is some purple fringing in the usual backlit situations. All in all, one of the better zooms of the year 1970.

Lousy light the last few days unfortunately.

The bird -

crop -

casualcollector · Posted: Tue Mar 17, 2009 11:57 am Post subject:

Very nice Luis. Another interesting lens rescued from obscurity. I had a Komura tele zoom in the mid 70s. It was a one touch 80-210, constant f4.5. It was a bit loose and wobbly so it got traded off quickly.

Oldhand · Posted: Thu Sep 19, 2019 12:09 am Post subject:

Excellent results Luis.
Here are a couple of shots from mine.
Tom

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luisalegria · Expire: 2018-01-18

And heâ€™s a very pretty boy isnâ€™t he?

If anyone in the US wants my lens free, please pm me. And if you want other free Komuras too.

blotafton · Joined: 08 Aug 2013 Posts: 1633 Location: Sweden

Very generous Like 1

Oldhand · Posted: Mon Apr 20, 2020 5:20 am Post subject:

I used this lens today with a closeup ring and hand held at high ISO, so a bit noisy.
Here we go.
Tom
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Minolfan · Joined: 30 Dec 2008 Posts: 3439 Location: Netherlands

Oldhand · Posted: Tue Apr 21, 2020 5:08 am Post subject:

A few more from this interesting lens.
More interestingly, with a small extension tube fitted, it is easier to focus by placing the focus ring at infinity and focusing with the zoom ring.
Tom
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55 · Expire: 2022-06-15

Thanks for sharing those beautiful shots, guys. I agree with Luis, the lens is a handsome one.
But it's large enough that I think it should've been made with a tripod collar. Fortunately, the collar from my junked Tokina 300mm f/5.5 lens fits on the Komura and doesn't interfere with the aperture ring.

The collar from an old, Tamron 300mm f/5.6 also fit onto the Komura, but I lost the tightening screw / knob for that one, so it was replaced with the Tokina collar.

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Oldhand · Posted: Sun Apr 26, 2020 6:37 am Post subject: