Aetna Rokunar (Sun Optics) 70-210/4 Auto Zoom

[luisalegria]

I've had this thing for quite a long time. It was purchased very cheaply with my Nikon FM. "Aetna" and "Rokunar" were trade names for a marketing company that sold the products of many makers, but the maker was Sun Optics, a very old Japanese optics firm, one of the first Japanese firms in the third-party lens business, and one of those that sold a great deal of product under its own name, instead of maintaining anonymity like Tokina, Komine, Kiron, Tomioka, Fujita, etc.



I wasn't going to document this here for a while longer, waiting to pick up its big brother the massive Sun Optics 80-240/4, but member badgerhill did a great job with it -

http://forum.mflenses.com/rokunar-70-210mm-f4-zoom-and-rokunar-200mm-f3-9-tele-t7867.html

- so I though I might as well give it a workout.

This is a rather interesting modernist ("space age") design of a "two touch" constant-aperture zoom, which was quite a technological achievement in 1969, along with its new automatic YS-universal mount - in my case, it was a Nikon mount. Unfortunately, this one does not maintain focus while zooming. Like many (but not all) YS lenses, this one is fully usable with manual aperture on a T-mount, and it even has a manual-auto switch, which would soon become extinct.

Its not a bad lens, very decently sharp when stopped down a bit and it has good contrast under challenging lighting. There is little worry about flare, and the built-in hood is excellent and extremely solid ! This is a heavy lens.

There are serious problems wide-open though, plenty of color fringing if given half a chance.

All in all, out of my similar two-touch zoom lenses from this period (late 1960's-early 1970's), the Kiron 85-205/3.8(mine is a Vivitar), Tokina 90-230/4.5 (Sears), and this one, this is probably the worst performer, and the Kiron is the best.











The bird, f/4 - you can see the fringing even uncropped -

[poilu]

superb results Luis!

p.s: you must have a big house to keep all those doorstop

[luisalegria]

This IS a pretty good doorstop !

It could probably survive that duty, and still work if someone wanted to take pictures with it.

Why do I keep all this stuff around ? Because I am a collector, which is a little like being an alcoholic.

[poilu]

[Attila]

I am really curious what you can do with a good lens, because you make all lens to looking excellent! Congrats mate! You are a good ambassador of not respected lenses.

[maddog10]

I like the lightpost and the car (like that it is mostly hidden in shadow).

Did you use noise reduction on the bird?

[luisalegria]

I didn't do anything with any of these (or any, period) save adjust the lighting/contrast (as I tend to underexpose) and get rid of dust spots sometimes. I don't trust those sharpening/de-noise things. I am a total dunce with post-processing.

Hi Attila, every lens is a good lens !

[Attila]

[zewrak]

That thing in the back of the lens, does it come off? I have a Tokina lens that have an "adapter" like that.