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Mysterious projection lens KO - 120" on G1
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PostPosted: Mon Mar 04, 2013 2:22 pm    Post subject: Mysterious projection lens KO - 120" on G1 Reply with quote
TThe pictures below were taken by a mysterious projection lens, probably made in the then USSR. Only got marking KO-120" 1:2,1 F=12cm written on it. Anyone has information on this lens? I am interested to learn more about it. Thank you!



















































Last edited by ferrick on Mon Mar 04, 2013 3:41 pm; edited 1 time in total


PostPosted: Mon Mar 04, 2013 3:17 pm    Post subject: Reply with quote
Wow, this is the best performing projector lens I've ever seen. Could you post some pics of the lens itself? I'm curious because the IQ looks superb to me.


PostPosted: Mon Mar 04, 2013 3:38 pm    Post subject: Reply with quote
iangreenhalgh1 wrote:
Wow, this is the best performing projector lens I've ever seen. Could you post some pics of the lens itself? I'm curious because the IQ looks superb to me.


This is the lens. Very Happy






PostPosted: Mon Mar 04, 2013 3:59 pm    Post subject: Reply with quote
the lens is great and your pics are first class, wow !


PostPosted: Mon Mar 04, 2013 5:31 pm    Post subject: Reply with quote
Very nice. How were you taking the pics? Holding the lens up to the camera?


PostPosted: Mon Mar 04, 2013 9:31 pm    Post subject: Reply with quote
Looks familiar. I own K0-120M (next generation?) which is 1.8/120 (slightly bigger judging from photos) and gives promising (contrasty and sharp) test results being hold in hand in front of the camera body. Construction is rather simple: two doublets, single coatings of purple color.


PostPosted: Mon Mar 04, 2013 9:47 pm    Post subject: Reply with quote
Who cares what it is? Wink It's a keeper ! Those are some fine images. Are you using an 'aperture' ? I use cardboard discs on my projector lens projects.

The dead leaf with the water droplets is stunning.


PostPosted: Mon Mar 04, 2013 10:01 pm    Post subject: Reply with quote
Nice defocus! Really nice lens!


PostPosted: Mon Mar 04, 2013 10:13 pm    Post subject: Reply with quote
poilu wrote:
the lens is great and your pics are first class, wow !


Thank you! Embarassed


PostPosted: Mon Mar 04, 2013 10:18 pm    Post subject: Reply with quote
cooltouch wrote:
Very nice. How were you taking the pics? Holding the lens up to the camera?


I used a Chinese made manual focusing helicoid. Its opening is M58 and rear end is M42. The flange distance of this lens is too short for normal DSLR, only sufficient for M4/3 to focus to infinity!


PostPosted: Mon Mar 04, 2013 10:21 pm    Post subject: Reply with quote
pavko wrote:
Looks familiar. I own K0-120M (next generation?) which is 1.8/120 (slightly bigger judging from photos) and gives promising (contrasty and sharp) test results being hold in hand in front of the camera body. Construction is rather simple: two doublets, single coatings of purple color.


Wow, f/1.8! Could you please post some pictures to share? I guess the bokeh should be even better! Smile Smile


PostPosted: Mon Mar 04, 2013 10:22 pm    Post subject: Reply with quote
Lloydy wrote:
Who cares what it is? Wink It's a keeper ! Those are some fine images. Are you using an 'aperture' ? I use cardboard discs on my projector lens projects.

The dead leaf with the water droplets is stunning.


Ys, I did. But just for reducing a little bit of incoming light since fogging is an issue with this lens. After adding the cardborad disc, the effective aperture is now around f/2.3.


PostPosted: Mon Mar 04, 2013 10:26 pm    Post subject: Reply with quote
simbon4o wrote:
Nice defocus! Really nice lens!


Thank you! Razz Razz


PostPosted: Mon Mar 04, 2013 10:50 pm    Post subject: Reply with quote
Lloydy wrote:
Who cares what it is? Wink It's a keeper ! Those are some fine images. Are you using an 'aperture' ? I use cardboard discs on my projector lens projects.

The dead leaf with the water droplets is stunning.


That's the shot I liked too, very fine gradation of tones, looks like it was taken with a very expensive lens.


PostPosted: Mon Mar 04, 2013 10:52 pm    Post subject: Reply with quote
First of all - stunning pictures (I should said that in my first post as it is reality we see. I focused myself however on question about technical details of the lens - I'm sorry about that)

ferrick wrote:
Wow, f/1.8! Could you please post some pictures to share?

I'll try to post some pictures of the lens in following days. Samples I have are unfortunately only technical snaps not to be posted here. I guess that this lens will wait until weather outside will be better (spring maybe?).

Lloydy wrote:
Who cares what it is?

It is only mine because it was in pack with Rathenower Optische Werke Visionar 1.6/77. If I knew earlier what kind of lens it is then I would have no doubts whether I'm doing good deal or not Wink. Besides - more information we share more value we add to this site and more we can find about rare items like this one...


PostPosted: Tue Mar 05, 2013 3:38 am    Post subject: Reply with quote


KO-120 and KO-120M AKA 35KP-1,8/120 (standartized name, "35mm projection lens 120mm f/1.8") - simlpe Petzval-type lenses with high field curvature. It's most distributed 35mm projection lenses over the FSU, because used in schools in epidiascope and other educational projectors.



Optical design: 4 elements in 2 groups, Petzval-type aplanat
Resolution(over the cine frame, same as the APS-C): 75/40 lp/mm (projection resolution, not photographic!)
Light transmission: 90%
Weight: 655gr.
Length: 150mm
Mount diameter: 62.5mm
Max. diameter: 77mm



PostPosted: Tue Mar 05, 2013 12:30 pm    Post subject: Reply with quote
Amazing shots ! I'm impressed by the shots quality and the "poor" apearance of the lens.... But results are perfect !


PostPosted: Tue Mar 05, 2013 2:13 pm    Post subject: Reply with quote
iangreenhalgh1 wrote:
Lloydy wrote:
Who cares what it is? Wink It's a keeper ! Those are some fine images. Are you using an 'aperture' ? I use cardboard discs on my projector lens projects.

The dead leaf with the water droplets is stunning.


That's the shot I liked too, very fine gradation of tones, looks like it was taken with a very expensive lens.


You will not gotta believe it. I bought it from eBay for just $0.01 USD (ending/only bid) plus $39.9 USD postage (i.e. total of $40.00 USD)! Laughing Laughing


PostPosted: Tue Mar 05, 2013 2:15 pm    Post subject: Reply with quote
pavko wrote:
First of all - stunning pictures (I should said that in my first post as it is reality we see. I focused myself however on question about technical details of the lens - I'm sorry about that)

ferrick wrote:
Wow, f/1.8! Could you please post some pictures to share?

I'll try to post some pictures of the lens in following days. Samples I have are unfortunately only technical snaps not to be posted here. I guess that this lens will wait until weather outside will be better (spring maybe?).

Lloydy wrote:
Who cares what it is?

It is only mine because it was in pack with Rathenower Optische Werke Visionar 1.6/77. If I knew earlier what kind of lens it is then I would have no doubts whether I'm doing good deal or not Wink. Besides - more information we share more value we add to this site and more we can find about rare items like this one...


Thank you! Please do share the photos when the weather is getting better in your part of the world. Smile


PostPosted: Tue Mar 05, 2013 2:18 pm    Post subject: Reply with quote
nukemall wrote:


KO-120 and KO-120M AKA 35KP-1,8/120 (standartized name, "35mm projection lens 120mm f/1.8") - simlpe Petzval-type lenses with high field curvature. It's most distributed 35mm projection lenses over the FSU, because used in schools in epidiascope and other educational projectors.



Optical design: 4 elements in 2 groups, Petzval-type aplanat
Resolution(over the cine frame, same as the APS-C): 75/40 lp/mm (projection resolution, not photographic!)
Light transmission: 90%
Weight: 655gr.
Length: 150mm
Mount diameter: 62.5mm
Max. diameter: 77mm



You are wonderful! Thanks for digging out the information on this lens. Now I know more about its design and specifications. Thanks once again! This forum is just resourceful! Smile


PostPosted: Tue Mar 05, 2013 2:20 pm    Post subject: Reply with quote
ManuallyYours wrote:
Amazing shots ! I'm impressed by the shots quality and the "poor" apearance of the lens.... But results are perfect !


Well said! Results are much more important than appearance. Smile


PostPosted: Tue Mar 05, 2013 10:10 pm    Post subject: Reply with quote
nukemall wrote:

Resolution(over the cine frame, same as the APS-C): 75/40 lp/mm (projection resolution, not photographic!)


Could any expert that is reading this forum explain what is the difference between projection and photographic resolution? And is there any way (besides test tables) to estimate later?


PostPosted: Tue Mar 05, 2013 11:52 pm    Post subject: Reply with quote
Measured photographic resolution depends on the film emulsion grain or(at digital cameras) on the sensor structure - Bayer matrix, antialias filter etc. Roughly photographic resolution 1.5 times less than the projection resolution.


PostPosted: Wed Mar 06, 2013 11:21 am    Post subject: Reply with quote
Thanks for explanation.

Assuming that I'm using foveon sensor (so no bayer, no AA filter) it stays the same as projection resolution but no more than resolution of sensor. Right?
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