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Lomo OKC 70 mm f/1.8 Russian projection lens
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PostPosted: Mon Feb 11, 2013 6:32 am    Post subject: Lomo OKC 70 mm f/1.8 Russian projection lens Reply with quote

Hello to everyone,
I've just got this lens from eBay:
http://www.ebay.com/itm/160871211521?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
to try it on my Nex-7. It will take some one more week till it arrives from Russia.
Till then I am wondering if someone has any experience with it as a taking lens. Any information is welcome.


PostPosted: Mon Feb 11, 2013 6:57 am    Post subject: Reply with quote

Would you mind sharing what the Best Offer price was? I see he has many more… Very Happy


PostPosted: Mon Feb 11, 2013 7:02 am    Post subject: Reply with quote

It was 80$, free shipping.


PostPosted: Mon Feb 11, 2013 7:04 am    Post subject: Reply with quote

Thx, good to know. It would be nice if any of the focal lengths (nearly) covers 6x6; then I can mount it on my Rolleiflex SL66E which has a bellows focus system.


PostPosted: Mon Feb 11, 2013 1:38 pm    Post subject: Reply with quote

Mentioned those some time ago, they don't seem to get sold fast.

I was intrigued by the glass but found them too expensive to just try out without built in aperture and focus control.
Very interesting to see your results.


PostPosted: Mon Feb 11, 2013 4:08 pm    Post subject: Reply with quote


Sony NEX5 & Zeiss Ikon Orikar lens by Mudplugga, on Flickr
This is a Zeiss Ikon Orikar 150 / 3.2 projector lens with no aperture or focus, I make the apertures from cardboard and cut a hole in the middle, I've experimented with holes from 5 mm to 20 mm and obviously get the same results as a lens with an iris. Luckily the Zeiss lens has a 52 mm thread so I use a reversing ring to fit it on the bellows for focusing, and it works superbly. I've had some good pictures from it.


PostPosted: Fri Mar 15, 2013 1:54 pm    Post subject: Reply with quote

I thought that my lens got lost on shipping but, surprisingly, it finally arrived today.
At first look it seems to be a very similar Petzval design with the KO-120/2.1 presented here:
http://forum.mflenses.com/mysterious-projection-lens-ko-120-on-g1-t57120.html
First impresion is positive, it seems to be quite sharp at f/1.8, with very nice bokeh and color but very shallow DOF, just like the KO-120/2.1 mentioned above. But that 's only what I could see with it provisionally tape-mounted.
In the next days I'll make it a proper mount and I'll post some tests.

rawhead - unfortunately it has a short register distance, probably 52.43 mm. as the KO-120/2.1, and it can't focus infinity on your SL66E. But is enough for a proper mount (with focusing helicoid) on a NEX.


PostPosted: Fri Mar 15, 2013 7:05 pm    Post subject: Reply with quote

Till then 2 in-house quick and boring sharpness tests on NEX-7 with the lens tape -mounted.
No PP, just in-camera jpg.

1- wide opened at f/1.8


100% center detail


2- With a front-mounted cardboard opening of between f/2.8 - f/4


100% center detail


100% up - right detail


100% down - left detail


PostPosted: Sat Mar 16, 2013 11:27 pm    Post subject: Reply with quote

very impressive. Smile


PostPosted: Sun Mar 17, 2013 4:32 pm    Post subject: Reply with quote

aspen wrote:
very impressive. Smile

So far it impressed me too.

And another on-window infinity test in a dull day, with the lens tape-mounted and a cardboard opening of 30 mm. This is approximately f/2.3. At this opening it shows a slightly magenta cast in the central area which is all gone by f/3.
I didn't expect the projection lens to behave well at infinity, but it surprised me.
Please note the enormous depth of field at f/2.3 from this angle. Probably this is due to the fact that the focusing plane is in fact spherical, like in those Minolta lenses with Variable Field Curvature on which you could change the DOF without changing the f-stop..

At f/2.3:


100% center


100% left-down


100% wright-up


PostPosted: Sun Mar 17, 2013 6:03 pm    Post subject: Reply with quote

CA is probably its downfall, but if this vanishes at workable apertures then it's fairly decent..


PostPosted: Mon Mar 18, 2013 3:59 pm    Post subject: Reply with quote

I've dismantled the lens today and it is not a Petzval type, it looks like a Double-Gauss type design very similar to the Pancolar 80mm/f1.8.