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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

78mm/F0.86 lens

W

Walter R

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From a batch of lenses purchased at a government auction, I have a Super Farron 76mm lens with a F0.87 aperture. I believe this was used by NASA for a "star tracker". I have held it up against a wall (front pointing out and the back element about a 1/2 inch away from the wall) and it looks like the image circle is enough to cover a full still camera 35mm field of view and more than enough for the Red sensor.

I will try to take some pictures later today, but in the meantime, here is the good and the bad. This is not for the faint of heart...

This is the base lens with iris, etc. and has the focus threads, but does not have a back to go into with mount, etc. I believe this normally screwed into whatever it was used for and the threads are for focus. From my limited knowledge of lenses, it looks like to use this lens on a Red you would need to have a rear cylinder created that received the focus threads on the lens and had a PL mount on the back. And of course you would have to figure out the correct location for the PL mount to get the back focus correct.

The lens includes a working iris that goes from F0.87 to F16. The iris ring has a gear ring on it that looks like it is Arri pitch.

On the front element there is a scratch (just a surface scrape but maybe 1" long), some blotches on the exterior and possibly some fungus on the inside surface. I think the front element would need to be removed and sent to someone like UltraFlat (http://www.ultraflat.com/). Inside are some dust specs that should probably be cleaned out. The rear element has some blotches, but looks like it might clean up.

Before I get around to photos, you can go to this page and scroll down and see a picture of one of these beasts:
http://forum.mflenses.com/i-won-a-zeiss-ultron-1-8-50mm-hows-that-t6704,start,15.html

Price? I have no idea what it is worth, but I thought someone here might have an interest or know more about these lenses. PM me an offer if you are interested.

If nobody is interested, I'll just keep it and someday probably send it to a lens tech. If someone buys it, they need to promise to post some footage some day if they get it working on their Red.

Please note that while I think it might be possible to make this work with a Red, I am not a lens tech and may be completely wrong ... which I'm sure someone will quickly tell me.
 
Any idea what flange focal distance it requires to focus to infinity? Hold the lens back up to the wall until the image it projects is in focus, and measure the distance from the very rear of the lens to the wall.
 
The most important thing is the back focus - distance from the vertex of the rear element to the image plane.

On the Zeiss 50mm f0.7 that Stanley Kubrick used, it was only 3 mm.

If there is not enough back focus to clear the sensor protector on the RED ONE then it does not and never will work.
 
I'm fascinated by these extreme f stop lenses like Sanjin showed in this thread

http://www.reduser.net/forum/showthread.php?p=305290

After the megapixel war (in DSLR) that killed the past years Leica, Rollei, Contax,... "optically highest standard" commercial argument, I wonder if quality of optics (and T stops) will come back to be the number 1 argument?

Patrick

I think I'll buy some Zeiss stock :-)
 
Probably won't work with Red

Probably won't work with Red

Hi guys,

Thanks for the questions and interest. I played with the lens a little more and now think that it probably won't work on Red because of the flange focal distance - as PerfectOptics suggested I held the back up to a wall again and the lens focused at a little under a half inch between the rear element and the wall with the subject in focus about 11 feet away.

It comes apart pretty easily since the various optical groups are just in threaded metal cylinders, so maybe there would be a way to re-space some elements to change the ffd.

It is probably most suited to use on a rangefinder.

Walter
 
Wasn't the olpf at 8mm from the sensor?
That's about .320" If the lens is imaging at 1/2" (.500") you might have enough room there.
 
You're right, Chuck, the OLPF is about 8mm in front of the sensor. This lens will probably work. Looks like it has a 40mm coverage area, so more than enough coverage for the S35mm sensor. It's just up to someone to fabricate a PL mount for it. Either way, it would be a tight fit.
 
Jeff Kilgroe said:
You're right, Chuck, the OLPF is about 8mm in front of the sensor. This lens will probably work. Looks like it has a 40mm coverage area, so more than enough coverage for the S35mm sensor. It's just up to someone to fabricate a PL mount for it. Either way, it would be a tight fit.
Click to expand...

Hi Jeff,

One thing though is that he was focusing on something at eleven feet. At infinity the rear element (assuming it is of a standard optical design for a prime) will be further back. It's a medium focale length lens so it is going to move some distance from 11' to infinity. I use to know the formula for calculating the travel for a given focale length and focus distance but my memory isn't quite what it use to be. lol
 
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