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ROW (Carl Zeiss Jena) Visionar f1.9 141mm
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PostPosted: Wed Jan 15, 2014 10:26 pm    Post subject: Reply with quote
Very impressive mod, welcome Kamosor!


PostPosted: Thu Jan 16, 2014 5:09 am    Post subject: Reply with quote
Very nice, how was it done? Btw. Georg confirmed 10, not 6 µm pixel size (I have the docu Georg mentioned here too now which leads to the 50 lpm resolution he has also mentioned.

Show pictures please taken with it!!

Last edited by kds315* on Thu Jan 16, 2014 6:42 am; edited 1 time in total


PostPosted: Thu Jan 16, 2014 5:54 am    Post subject: Reply with quote
Kamosor wrote:
dan_ wrote:

I have the 100mm f/1.6 version of "Visionar"(without diaphragm and focusing helicoid) and I like it very much.
Welcome Smile So here it is Visionar 100/1.6 with diaphragm,focusing helicoid, lens hood, PK mount made by Marek Mazur from Poland.

Very nice!
How was it done? The focusing helicoid is simple to adapt and I'll do it soon but to add the diaphragm is very, very difficult.
I've dismantled my Visionar and the distance between the front and back lens groups, where the diaphragm should be, is only~0,5 mm. My conclusion was that it's almost impossible to adapt a diaphragm to it unless someone increases the distance between front and back groups. And the diaphragm unit should have enormous diameter mounting threads - I couldn't find one suitable.
What type of diaphragm unit did Marek Mazur used?


PostPosted: Thu Jan 16, 2014 6:04 am    Post subject: Reply with quote
Edmund Optics has about any size of iris (up to 300mm!!), just expensive, but not hard to find.


(c) Edmund Optics

Last edited by kds315* on Thu Jan 16, 2014 7:33 am; edited 1 time in total


PostPosted: Thu Jan 16, 2014 6:52 am    Post subject: Reply with quote
Thanks Klaus, I didn't know that.
Unfortunately quite expensive for large sizes and still remains the to solve the problem with the very narrow distance between front and back elements.


PostPosted: Thu Jan 16, 2014 7:16 am    Post subject: Reply with quote
Honestly, I do not know how Mark did it. I know he is a master of optics. He made first wooden amber lens. The modification was not cheap, but the quality of images is worth it.

kds315* thanks for correct pixel's datas. I found fresh Georg's informations at this side: http://oldlenses.blogspot.com/2013/06/carl-zeiss-jena-visionar-92mm-f16-photo.html

Author of the blog has a beautiful portfolio made ​​old manual lenses, including Visionars, too.


PostPosted: Thu Jan 16, 2014 7:37 am    Post subject: Reply with quote
Thanks, I know that Blog. Georg is a member here and has written about it here (scroll down a bit):
http://forum.mflenses.com/rathenower-visionar-oder-zeiss-visionar-t51692,highlight,%2Bvisionar.html

"The resolution of those lenses (fully open, no aperture) reached 10µm from center to 10mm off center and then
gradually declines to 20 µm at 15 mm (circle of 30 mm) and is therefor suitable for a lot of CCD or CMOS sensors
with similar µm pixel size (or via binning) for example in astronomy."


PostPosted: Thu Jan 16, 2014 8:03 am    Post subject: Reply with quote
Stock iris at reasonable price Click here to see on Ebay.

Some lenses Double Gauss have a very limited space distance between front and back elements. For example, the NIKKOR-N 5cm f/1.1. If you look at its optical diagram, there is only cardboard thin space between the two center groups. ~0.5mm is enough if you have a iris large enough. The cost for modification is high as it is not easy to insert the iris into the optical center exactly.

Congrats for all who own those Visionar(s). Wink


PostPosted: Thu Jan 16, 2014 9:11 am    Post subject: Reply with quote
One of the possible procedures to insert the iris into projection lens:

0, Open the lens to evaluate the possibility of installing the iris. Drop down the measurements.

1, Buy a proper iris which large enough to cover the lens and not bigger than the internal diameter of the lens barrel.

2, Locate the optical center of the lens from diagrams or measure it yourself.

3, Remove the glass from the top or the button. This is to allow you to put the aperture into the optical center.

4, Cut a small opening near the optical center to make rooms for the control rod. Drill holes on the lens barrel and the rim of the iris such that you can use screw to fix the aperture in the exact optical center.

5, Fix the iris by stop screws. If the size of the iris is not exactly fit the lens barrel, fix it with a longer stop screw. You will need to cover the space between the lens barrel and iris in the last step to prevent light leak.

6, Put the control rod control rod back, put one element back and test the iris before you put all the other elements back.

7, (Optional)Make a aperture ring with marking and install it to the lens.

Done. Wink


PostPosted: Thu Jan 16, 2014 2:41 pm    Post subject: Reply with quote
Yes, it is really simple, isn't it? Wink


PostPosted: Thu Jan 16, 2014 3:17 pm    Post subject: Reply with quote
kds315* wrote:
Yes, it is really simple, isn't it? Wink

This take me a while to think and type it down. It is not a simple task but anyone with the tools and enthusiasm should be able to do it sooner or later. You can always outsource it to a professional if you have enough money. Wink


PostPosted: Thu Jan 16, 2014 7:26 pm    Post subject: Reply with quote
calvin83 wrote:
...anyone with the tools and enthusiasm...

That's the point where real challenge is. Access to proper tools. I'm in situation where there is optimism and enthusiasm however access to proper (meaning lathe and friends) tools is limited. So stock of strange albeit high quality and wonderful lenses without use is big... Lately I've started to limit myself - however because of LBA it's tough topic.

BTW. I own Visionar 77/1.6 and i'm also wondering how to make it first class citizen of my photographic bodies.


PostPosted: Thu Jan 16, 2014 9:23 pm    Post subject: Reply with quote
Well I just received my ROW 1.6/100mm in mint condition (€25) except for some 1st stage fungus - should clean up without issues.

Like Dan said the rear group (4-6) is housed in a sub assembly which easily unscrews with a lens wrench.

It is important to understand how the iris has effect on the lens performance.

But first, I will assume some of you have "a little bit " of optical knowledge..... Smile






The pictures show a DG lens approx f=100mm and the effect on the misleadingly described center of the lens. In fact the iris has brought this center of lens forward from the face of the 4th element.

The ROW lens has no space in the middle so is more complicated, but a simple experiment with thick cardboard apertures can be done to see if a solution is possible. An iterative procedure of inserting an aperture and observing the effect of the increased track length can tell if it works.

Then replace with good old Chinese stock Smile


PostPosted: Fri Jan 17, 2014 12:21 am    Post subject: Reply with quote
Even the Chinese diaphragms from ebay are not cheap with the iris dimension >60mm(~ 80-90$) and they are hard to find. Only little ones are common and cheap.

I have adapted a diaphragm to a projection lens before and I have both the tools and access to a lathe operated by an enthusiast who appreciates more the challenge then my money and therefore charges me cheap. I'd say I am in a privileged position from this point of view, but...
The Visionar is very heavy and I love its special character mostly wide open or near wide open. For landscape-type photos with a big DOF, when a closed diaphragm is more useful, I think that other lenses are more suitable.
Such being the case I think that I'll test it with different cardboard openings till I'll get the best (for me) DOF/bokeh/sharpeness for portraits and I'll simply give it that between-the-lens opening. Till now it looks like a f/2.1-f/2.5 opening is the best as it reduces the CA as well. This opening, metal made, can be easily mounted in the proper place because the front lens group has a 37mm threaded mount-opening at its back.

Anyway, testing a projection lens for slightly increased distance between front and back groups proved, in my experience, to be useful.
At least with one lens (Hermagis Cinema 50mm) increasing that distance proved to substantially and unexpectedly increase the lens resolution.

Of course that, in spite of everything, owning a Visionar with a between-the-lens iris and focussing helicoid like the ones presented here would make me happy like a child. Very Happy


PostPosted: Fri Jan 17, 2014 12:49 am    Post subject: Reply with quote
dan_ wrote:
Even the Chinese diaphragms from ebay are not cheap with the iris dimension >60mm(~ 80-90$) and they are hard to find. Only little ones are common and cheap.



Dont forget it is the entrance pupil which is used for Fstop. So the actual aperture can be a lot smaller because it is magnified by the front group (1-3)

Best way to check is to place a piece of paper inside with mm markings, then count the markings from looking from the front of lens and then when the paper is outside you will know the correct physical aperture size which gives F1.6


PostPosted: Fri Jan 17, 2014 1:48 am    Post subject: Reply with quote
JohnBar wrote:
Best way to check is to place a piece of paper inside with mm markings, then count the markings from looking from the front of lens and then when the paper is outside you will know the correct physical aperture size which gives F1.6

I didn't know that. Thanks, I'll try it.

My method is to measure with a micrometer the diameters of the lenses placed immediately up and down to the intended iris position and count the diameter of the useful opening of the iris (their media if the diaphragm will be at half-distance between them).
That media I assume to be the iris opening diameter for the nominal f value of the lens (~ 36 mm for f/1.6 in the case of the Visionar 100mm, if I remember well).
Then, for counting the iris diameter for different f.stops I use the property that closing the iris with one f.stop means decreasing the opening surface of the iris with a factor of 1/2(ex.: iris opening surface for f/2.8 = iris opening surface for f/2 x 1/2). This way I can count the iris diameter for different f.stops and I can calibrate the diaphragm quite accurate.
Am I wrong somewhere?

In the case of the Visionar, because of the narrow distance between front and back groups, unfortunately the iris of the diaphragm should be, I imagine, about as large as the barrel (with only a 36mm useful opening - the rest is lost because of mounting the diaphragm in that narrow position and the large dimensions of the inner mounts).
Otherwise the distance between front and back groups should be increased substantially, with the maximum thickness of the diaphragm unit used + mounting threads thickness.


PostPosted: Fri Jan 17, 2014 3:29 am    Post subject: Reply with quote
dan_ wrote:
Even the Chinese diaphragms from ebay are not cheap with the iris dimension >60mm(~ 80-90$) and they are hard to find. Only little ones are common and cheap.

$80-90 is enough to make one in custom size if you know the right person. It is possible to take the iris from a large zoom but it may be even more difficult than a stock iris. I think it will be more fun if we can make an opening on the barrel it for aperture inserts... It can be heart sharped, triangular sharped or whatever shape you want.


PostPosted: Fri Jan 17, 2014 1:38 pm    Post subject: Reply with quote
dan_ wrote:


My method is to measure with a micrometer the diameters of the lenses placed immediately up and down to the intended iris position and count the diameter of the useful opening of the iris (their media if the diaphragm will be at half-distance between them).
That media I assume to be the iris opening diameter for the nominal f value of the lens (~ 36 mm for f/1.6 in the case of the Visionar 100mm, if I remember well).
Then, for counting the iris diameter for different f.stops I use the property that closing the iris with one f.stop means decreasing the opening surface of the iris with a factor of 1/2(ex.: iris opening surface for f/2.8 = iris opening surface for f/2 x 1/2). This way I can count the iris diameter for different f.stops and I can calibrate the diaphragm quite accurate.
Am I wrong somewhere?.


Your technique seems fine to me. 37-38mm is what I measure for F1.6, but F3.2 will be ~ 19mm

Also unscrew the rear cell a little 2-3mm and check the effect on image quality.

I am trying to free the front section, I have removed the grub screw and put penetrating oil on the threaded joint, but it may be threadlocked.

Were you successful in removing the front section?


PostPosted: Fri Jan 17, 2014 2:05 pm    Post subject: Reply with quote
JohnBar wrote:
Were you successful in removing the front section?

Yes, I succeeded in removing it.


PostPosted: Fri Jan 17, 2014 2:43 pm    Post subject: Reply with quote
Good, so no threadlock Smile


PostPosted: Fri Jan 17, 2014 5:34 pm    Post subject: Reply with quote
OK, the oil finally penetrated and I now have the front off.

I can see maybe a 3mm recess behind the 3rd element but this this overlaps with the rear cell, so an elegant solution would be tricky and cost maybe €300+ for labour alone.

The cheapest solution and one which I will adopt is to cut some steel shim 100 micron using a compass and sharpie to create thin apertures which fit in the recess (dia 37mm) and darken them with felt pen.

This procedure will not be much more difficult to changing a M42 lens Smile

I might even make a scalloped iris to mimic a Cooke S4 lens for fun. Smile


PostPosted: Fri Jan 17, 2014 11:41 pm    Post subject: Reply with quote
JohnBar wrote:
The cheapest solution and one which I will adopt is to cut some steel shim 100 micron using a compass and sharpie to create thin apertures which fit in the recess (dia 37mm) and darken them with felt pen.


That's not so much different of what I said I'll do Smile
The dia 37 mm. back opening of the front group is threaded(37/0.5). I'll make(lathe) some brass openings to screw in it (1.5 mm. thickness) and I'll blacken them with gun brass blackening solution.

Jhon, if you test the apertures please let me know witch one you think that gives the best sharpeness/DOF/bockeh /CA compromise for portrait and witch for close up.


PostPosted: Sat Jan 18, 2014 10:05 am    Post subject: Reply with quote
Nice to read about the progress you are making guys!


PostPosted: Sat Jan 18, 2014 11:19 am    Post subject: Reply with quote
What's the diameter of this 1.6/100? I'm wondering if I could mount one in a shutter for use on 6x9.


PostPosted: Sat Jan 18, 2014 11:40 am    Post subject: Reply with quote
62.5mm rear (russian standard for proj. lenses)
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