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Carl Zeiss Jena 50mm f0.77
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PostPosted: Wed Mar 25, 2009 11:05 pm    Post subject: Carl Zeiss Jena 50mm f0.77 Reply with quote
WTF?

Click here to see on Ebay


Although the sample pictures aren't overwhelming or anything, but the video he shot with it is interesting, from an abstract POV.


http://www.marcocordero.com/zeissf0.7.mov

Last edited by rawhead on Thu Mar 26, 2009 12:19 am; edited 2 times in total


PostPosted: Wed Mar 25, 2009 11:34 pm    Post subject: Reply with quote
Well that didn't take long to get removed Laughing


PostPosted: Thu Mar 26, 2009 12:03 am    Post subject: Reply with quote
The link just seems to be messed up. Try this one.


PostPosted: Thu Mar 26, 2009 12:20 am    Post subject: Reply with quote
Oops, yeah, sorry, I keep forgetting that all I need is the item number between the tags Embarassed Fixed the original (thanks!)


PostPosted: Thu Mar 26, 2009 1:09 am    Post subject: Reply with quote
thats a fake right?

zeiss only made a 0.7?


PostPosted: Thu Mar 26, 2009 2:53 pm    Post subject: Reply with quote
Well it is funny if you see your (ex) own lens and the adaptor I had designed for it being sold off to make some profit. But that's life I guess....

The lens IS indeed genuine, comes from an older Zeiss Jena Xray system which needed to capture "every photon" to keep the Xray dosage low for the patient. very impressive lens (I call those "monster lumen lenses") but the back focal distance is very shallow, so only fixed focus macro is possible.

Nevertheless, very artistic pictures may be done with such one...

That one is even a bit faster:



and it does that (now that I call bokeh ... Wink ):



Carl Zeiss Jena also made such lenses:



PostPosted: Thu Mar 26, 2009 5:37 pm    Post subject: Reply with quote
What dreamy lenses you have, Klaus. Surprised


PostPosted: Thu Mar 26, 2009 5:45 pm    Post subject: Reply with quote
The R-Biotar isn't biotar-based, is it?


PostPosted: Thu Mar 26, 2009 5:57 pm    Post subject: Reply with quote
no-X wrote:
The R-Biotar isn't biotar-based, is it?


Of course it is. It is Zeiss naming convention, if it has BIOTAR outside, there will be BIOTAR inside - don't forget this is still Germany!! Wink Wink

R-Biotar stands for R(=ROENTGEN=XRAY)-Biotar


PostPosted: Thu Mar 26, 2009 5:58 pm    Post subject: Reply with quote
koji wrote:
What dreamy lenses you have, Klaus. Surprised


I'll happily revert that compliment Koji!!


PostPosted: Thu Mar 26, 2009 6:08 pm    Post subject: Reply with quote
kds315* wrote:
no-X wrote:
The R-Biotar isn't biotar-based, is it?


Of course it is. It is Zeiss naming convention, if it has BIOTAR outside, there will be BIOTAR inside - don't forget this is still Germany!! Wink Wink

R-Biotar stands for R(=ROENTGEN=XRAY)-Biotar

I'm confused... I think I read somewhere, that the lens is some triplet derivate. I'll try to find optical diagram Smile


PostPosted: Thu Mar 26, 2009 6:24 pm    Post subject: Reply with quote
Holy moly..... what lenses you have!!

And here I was drooling over Noctiluxes and Angenieux C-mount 25mm lenses with measly f0.9~f1.0 apertures Laughing


PostPosted: Thu Mar 26, 2009 7:07 pm    Post subject: Reply with quote
Would make for a nice artsy portrait lens on a M42 focusing helicoid (I've seen those for sale) put on a Micro 4/3 camera! Could someone please try this on human subjects? Smile


PostPosted: Thu Mar 26, 2009 8:13 pm    Post subject: Reply with quote
no-X wrote:
kds315* wrote:
no-X wrote:
The R-Biotar isn't biotar-based, is it?


Of course it is. It is Zeiss naming convention, if it has BIOTAR outside, there will be BIOTAR inside - don't forget this is still Germany!! Wink Wink

R-Biotar stands for R(=ROENTGEN=XRAY)-Biotar

I'm confused... I think I read somewhere, that the lens is some triplet derivate. I'll try to find optical diagram Smile


It is a PETZVAL lens derivative actually, look here
http://books.google.com/books?id=wrtFcUEIWTgC&pg=PA276&lpg=PA276&dq=R-Biotar&source=bl&ots=z4B9t7gCFm&sig=GZgct5KDCVrE5W7tEo2GDXRqges&hl=de&ei=0ODLSbDNM5CpsAbopempCA&sa=X&oi=book_result&resnum=7&ct=result

or here:
http://books.google.com/books?id=OJrJrEJ-r9QC&pg=PA43&lpg=PA43&dq=R-Biotar&source=bl&ots=YY2p5TA-5E&sig=6ex3QdvhOB8tDK_Kl9xALnM9ZjM&hl=de&ei=0ODLSbDNM5CpsAbopempCA&sa=X&oi=book_result&resnum=10&ct=result


PostPosted: Thu Mar 26, 2009 8:17 pm    Post subject: Reply with quote
aoleg wrote:
Would make for a nice artsy portrait lens on a M42 focusing helicoid (I've seen those for sale) put on a Micro 4/3 camera! Could someone please try this on human subjects? Smile


Well I have such a special ultra slim helicoid made for my Nikon, having a front M42 thread mount. Actually I use it with such lenses to give it "some" focusing. Never took a portrait though, since the image angle would not allow that, and someones nose alone is not that pretty. Maybe an eye and lashes would be??


PostPosted: Tue Apr 17, 2018 10:56 am    Post subject: Reply with quote
I have this, $500 including shipping and original mounting frame. PM if interested.


PostPosted: Tue Feb 07, 2023 6:55 pm    Post subject: Reply with quote
I stumbled about this lens on Ebay. Quite surprising to see a f/0,77 50mm from Zeiss Jena. It should be heavy.

https://www.ebay.de/itm/314330277195
https://www.ebay.de/itm/325481767042

The issue with it is how to adapt it? I first thought this would be cinema lenses with a screw mount. The sellers did not know anything about this lens so they did not mention any mounting options. Since it is Zeiss it will be some industry standard screw mount but you need to find out which one and create a helicoid solution for it.

@Klaus Can you give us some information about how you adapted it? Could it be usable on a mirrorless camera with a short flange distance?


PostPosted: Tue Feb 07, 2023 7:02 pm    Post subject: Reply with quote
Is it worth it for the price? These aren't meant to cover very large formats, so your equivalent depth of field will well be in range of a 50mm f1.4 on full frame, for instance.

Nevertheless you could ask RAFcamera to make you a thread adapter if you bought it.


PostPosted: Tue Feb 07, 2023 7:10 pm    Post subject: Reply with quote
eggplant wrote:
your equivalent depth of field will well be in range of a 50mm f1.4 on full frame, for instance.


No.

S


PostPosted: Tue Feb 07, 2023 8:28 pm    Post subject: Reply with quote
stevemark wrote:
eggplant wrote:
your equivalent depth of field will well be in range of a 50mm f1.4 on full frame, for instance.


No.

S


Sorry, brain fart. Wrong focal length- it would NOT look like a 50mm lens.

It would only ever cover micro four thirds at max at infinity, usually somewhere inbetween a 1 inch sensor and micro four thirds. I can provide numbers on this.

So you can multiply the focal length and equivalent depth of field by the crop factor. This is valid.


PostPosted: Tue Feb 07, 2023 11:31 pm    Post subject: Reply with quote
eggplant wrote:
stevemark wrote:
eggplant wrote:
your equivalent depth of field will well be in range of a 50mm f1.4 on full frame, for instance.


No.

S


Sorry, brain fart. Wrong focal length- it would NOT look like a 50mm lens.

It would only ever cover micro four thirds at max at infinity, usually somewhere inbetween a 1 inch sensor and micro four thirds. I can provide numbers on this.

So you can multiply the focal length and equivalent depth of field by the crop factor. This is valid.


We have had this before - basically the same discussion as here, but back then the question was "DOF of medium format 6x4.5 cm lenses vs 24x36mm lenses". Back then some people were adamant that a medium format lens of a certain focal length has a shallower DOF than a 24x35mm lens of the same focal length (at the same aperture, of course). This simply is not true, and I did prove it, providing images taken with the Mamyia Sekor C 1.9/80mm vs the MinAF 1.4/85mm. Google it.

It is important to know that the DOF of a lens has nothing to with its image circle: The 4/50mm superwide for the Pentax 67 has exactly the same DOF as a common normal lens for Full Frame (when stopped down to f4). And both have the same DOF as a 50mm tele lens for 8mm film (again if you stop it down to f4, of course).

If you now think that the R-Biotar 0.77/50mm at 1.4 would have a different DOF than any other 1.4/50mm lens at f1.4, you are wrong.
In fact, the R-Biotar 0.77/50mm (hypothetically) stopped down to f1.4 would have exactly the same DOF as any other 50mm at f1.4.


Now ...do you really think that opening the aperture from f1.4 to f0.77 would NOT change the DOF? Go figure out ... Wink

S

EDIT: the image circle of those X-ray lenses usually is quite large. There are filmmakers out there using them even at or near infinity (with modified cameras, of course). The 100mm R-Biotar e. g. covers IMAX (48x70mm). Therefore I would expect the 50mm R-Biotar to cover at least half frame (18x24). Check it out.


PostPosted: Wed Feb 08, 2023 12:14 am    Post subject: Reply with quote
stevemark wrote:


We have had this before - basically the same discussion as here, but back then the question was "DOF of medium format 6x4.5 cm lenses vs 24x36mm lenses". Back then some people were adamant that a medium format lens of a certain focal length has a shallower DOF than a 24x35mm lens of the same focal length (at the same aperture, of course).


Yeah I'm not sure I disagree here so you'll have to clarify more specifically what you take issue with.

stevemark wrote:

It is important to know that the DOF of a lens has nothing to with its image circle: The 4/50mm superwide for the Pentax 67 has exactly the same DOF as a common normal lens for Full Frame (when stopped down to f4). And both have the same DOF as a 50mm tele lens for 8mm film (again if you stop it down to f4, of course).


I think you missed the words I was using - "apparent", "equivalent" or what I could add here - "looks like"

Yes, a 50mm f4 lens is like any other 50mm f4 lens. But all I'm taking issue with is what happens when you put film/image sensor behind them!



[quote="stevemark"]
If you now think that the R-Biotar 0.77/50mm at 1.4 would have a different DOF than any other 1.4/50mm lens at f1.4, you are wrong.
In fact, the R-Biotar 0.77/50mm (hypothetically) [b]stopped down to f1.4 would have exactly the same DOF as any other 50mm at f1.4[/b].

Err yeah, I agree.


stevemark wrote:

EDIT: the image circle of those X-ray lenses usually is quite large.


Simply untrue. The image circle of these is usually not large for various reasons. This is not a matter of interpretation, other members can attest to this.

It is a matter of the optical designs commonly chosen for (non-macro) X-ray lenses, and why they are so common in the 50mm range. I can tell you it's not because they were using a normal angle of view lens! Find me even an APS-C lens at a fast speed which has such a reduced small element diameter like this, relative to the front.

The vast majority at this speed at this focal length, are designed to be excellent over a small film/image diameter. This is why the rear element is so dramatically smaller than the front.

Lets take this Rodenstock example for instance, given at 100mm from 1970 - almost a full decade after the infamous 'TV-Heligon' patents.



At 100mm it just cover APS-C. This design like many others was scaled up and down throughout the focal lengths for infinity objectives, and that includes scaling up and down the coverage.

Here is the 'Rayxar' patent from 1959. Note 4mm less image circle, at 100mm. But faster.




The R-Biotar 100mm is the exception, not the rule. It's even more exceptional because it's derived from a Double-Gauss design, which is very rare for these. It's highly likely because no other optical design at this speed could easily cover 70mm film at 100mm with a flat field - certainly not Petzvals and definitely not 'Rayxar-like' designs which don't even cover 35mm at 100mm.

That is why the image circle is large.
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