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Singer Librascope f1.8 300mm mirror lens
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PostPosted: Thu Sep 15, 2016 7:37 am    Post subject: Singer Librascope f1.8 300mm mirror lens Reply with quote

Seen here Click here to see on Ebay

a very interesting fast mirror lens, most likely used for missile tracking.


(c) shphoto.eu


PostPosted: Thu Sep 15, 2016 7:43 am    Post subject: Reply with quote



PostPosted: Thu Sep 15, 2016 9:48 am    Post subject: Reply with quote

Yes please!


PostPosted: Thu Sep 15, 2016 3:17 pm    Post subject: Reply with quote

Very fast mirror lenses are quite a nightmare to use, extremely shallow DOF Wink


PostPosted: Thu Sep 15, 2016 3:22 pm    Post subject: Reply with quote

Do you think it covers 24x36?


PostPosted: Thu Sep 15, 2016 3:33 pm    Post subject: Reply with quote

Better get a Nikkor 300mm F2.0 if one need such fast lens.


PostPosted: Thu Sep 15, 2016 8:00 pm    Post subject: Reply with quote

BurstMox wrote:
Do you think it covers 24x36?


I rather doubt it...


PostPosted: Thu Sep 15, 2016 10:51 pm    Post subject: Reply with quote

kds315* wrote:
Very fast mirror lenses are quite a nightmare to use, extremely shallow DOF Wink

Impossible to get sharp image for sure, even 300mm f4.5 Rubinar is pretty painful to use well in distance shoots.
For tracking don't need to have sharp image.


PostPosted: Thu Sep 15, 2016 11:58 pm    Post subject: Reply with quote

Out of curiosity, what is this lens designed for (mount and usage)?


PostPosted: Fri Sep 16, 2016 12:56 am    Post subject: Reply with quote

I think for tracking need damn good precise auto-focus! Wink

Why does nobody introduce fast mirror with micrometer adjustment of focus ring? Focus "throw" too short usual problem...


PostPosted: Fri Sep 16, 2016 6:45 am    Post subject: Reply with quote

Boris_Akunin wrote:
BurstMox wrote:
Do you think it covers 24x36?


I rather doubt it...


Excellent Find!!!

So there have been three such high-speed, high - resolution catadioptric lenses:
300mm f/1.8, 500mm f/3.25, and 600mm f/1.8
made to fit a two-stage image intensifier system, which most likely had 15mm resp.
25mm image diamater, meaning the lens was also designed to only cover such small circles.

Here someone testing such an early system at night, not very convincing: https://www.youtube.com/watch?v=A0QacQKbv3E

Found an image of such a night vision system:


as as coincidence just wants it, here is one for sale Click here to see on Ebay



Here from the Bievre Camera Show 2008, someone testing the 500mm version of it

which was mentioned to be in Exakta mount (!?) and strangely enough has the same serial number 1027
as the one auctioned f1.8/300mm on ebay now (??)

So, enough "Lens Sherlock" work ....


Last edited by kds315* on Sun Sep 18, 2016 12:03 am; edited 1 time in total


PostPosted: Sat Sep 17, 2016 6:48 pm    Post subject: Reply with quote

visualopsins wrote:
...
Why does nobody introduce fast mirror with micrometer adjustment of focus ring? Focus "throw" too short usual problem...


Quoting myself, I know. Rolling Eyes

Some background for the idea. In 1970s I was Electronics Technician working on Instrumentation. The oscilloscopes of that time had manual dials for some adjustments. The potentiometers were limited to about 300 degrees of turn. To make fine adjustments, the knobs actually had inside little transmissions with differential gears -- a big turning of the knob would make a tiny turning of the adjustment potentiometer.

The idea seems simple enough to implement on mirror lens. The big diameter focus rings could be turned by a tiny knob -- knob is geared into the focus ring -- many turns of little knob turns focus ring tiny amount...


PostPosted: Sat Sep 17, 2016 8:24 pm    Post subject: Reply with quote

visualopsins wrote:
In 1970s I was Electronics Technician working on Instrumentation.

Really, buddy? I know one or two things about electronic instrumentation, too. Smile

Microscopes have a fine and a coarse adjustment of focus. Very practical. Supertelephoto lenses would also benefit from a focusing system similar to the microscopes.

Regarding the Singer Librascope, since it was used to track distant objects, the focus shouldn't be as critical as it seems at first sight. For example, when a 300mm F1.8 lens is focused to a distance of 5000 m, the depth of field extends from 2500m to infinity (for a confusion circle of 0.01mm). This means that the Singer Librascope could operate with fixed focus in many practical situations!

Great find, Klaus! The lens is yours?


PostPosted: Sat Sep 17, 2016 9:58 pm    Post subject: Reply with quote

Gerald wrote:
visualopsins wrote:
In 1970s I was Electronics Technician working on Instrumentation.

Really, buddy? I know one or two things about electronic instrumentation, too. Smile


Temperature-compensated precision 5-1/2 digit dual-slope integrating multi-meters, high-speed frequency counters & pulse generators, precision voltage references used for calibrating other instruments, microwave frequency generators for calibrating other communication devices...


PostPosted: Sat Sep 17, 2016 11:59 pm    Post subject: Reply with quote

Gerald wrote:
visualopsins wrote:
In 1970s I was Electronics Technician working on Instrumentation.

Really, buddy? I know one or two things about electronic instrumentation, too. Smile

Microscopes have a fine and a coarse adjustment of focus. Very practical. Supertelephoto lenses would also benefit from a focusing system similar to the microscopes.

Regarding the Singer Librascope, since it was used to track distant objects, the focus shouldn't be as critical as it seems at first sight. For example, when a 300mm F1.8 lens is focused to a distance of 5000 m, the depth of field extends from 2500m to infinity (for a confusion circle of 0.01mm). This means that the Singer Librascope could operate with fixed focus in many practical situations!

Great find, Klaus! The lens is yours?




You did not read all through I guess. I was used as a night vision system front lens for police enforcement
and users complaint that it was impossible to focus correctly to moving cars!

It is an ebay ad of a professional seller, of course not mine. Wink


PostPosted: Sun Sep 18, 2016 12:45 am    Post subject: Reply with quote

visualopsins wrote:
Temperature-compensated precision 5-1/2 digit dual-slope integrating multi-meters, high-speed frequency counters & pulse generators, precision voltage references used for calibrating other instruments, microwave frequency generators for calibrating other communication devices...

That's very cool! All the techniques you mentioned are very interesting and familiar to me. Because the last thing I want is going off-topic, I'll mention just one subject I worked on recently: FM-CW short-range radar.

Going back to topic, just out of curiosity I searched the specifications of one of the most famous telescopes in the world, the 200-inch Hale Telescope on Palomar Mountain:

Focal lenght (Cassegrain focus): 81,300 mm
Aperture: F16

Focal lenght (coudé focus): 152,000 mm
Aperture: F30

The apertures not very impressive, but the focal lengths, oh my God!


PostPosted: Sun Sep 18, 2016 12:57 am    Post subject: Reply with quote

kds315* wrote:

You did not read all through I guess. I was used as a night vision system front lens for police enforcement
and users complaint that it was impossible to focus correctly to moving cars!


Yes, police use certainly is not a good application for this lens. I based my comments on the following information:

kds315* wrote:
a very interesting fast mirror lens, Most Likely used for missile tracking.


Quote:

The primary function of the Mk 37 NVS is long-range observation, such as enemy surveillance and target detection.


PostPosted: Sun Sep 18, 2016 10:07 am    Post subject: Reply with quote

Wink Wink Wink


PostPosted: Fri Jun 10, 2022 12:48 pm    Post subject: Reply with quote

This is an old thread, but it seems right to continue it, because I think the same lens that has been previously mentioned is now for sale again on eBay: https://www.ebay.com/itm/295031157673

Serial number 1027, 300mm f1.8

I don’t see photos from the original post anymore, so I suspect they were lost when the forum was upgraded or something. I’ll post some of the listing photos. The seller is selling it combined with a Sony A7 and some custom-made adapters. In some research, I found that this lens was designed to be used with a light-amplification device, very different from being adapted to a mirrorless camera. The amplification devices are not part of this item being sold.

A resource I found is on Google Books; an evaluation of the system being used for police work; it was rejected as unworkable.
https://books.google.com/books?id=Jf5F3_qMMwAC&q=singer+librascope

I also found Librascope ex-employees have scanned and archived company newsletters (internal, I guess) but I didn’t yet see this lens mentioned in any of them.
https://www.evernote.com/pub/4sorenca/librascopesearch







PostPosted: Fri Jun 10, 2022 1:47 pm    Post subject: Reply with quote

US $3400 Laugh 1

Just read again and realised the camera is included - but it's a first generation Sony A7.

Even with it included not sure how it's worth this much... then again they are selling projection lenses which go for $99 stuck in helicoids for $400... https://www.ebay.com/itm/FAST-140mm-1-8-lens-for-Pentax-6x7-67-Aero-Ektar-Mamiya-645-GFX-135-165-Cinelux

Out of sheer coincidence I archived a listing for a Librascope 300mm and 500mm that had been going unsold for ages. They eventually came to as low as £150 for the 300mm one- no kidding. Then they sold.

https://archive.ph/zwbrD 300mm
https://archive.ph/zEFfg 500mm

With all that out of the way...


I am curious how you found this evernote website- never heard of it, who shared this?

As for information, I can find this specific model and the others offered as a lens for 35mm SLRs, motion picture and TV cameras in 1970-1971:

The reference is for this:

Industrial Photography 1970-09: Vol 19 Iss 9 p.90


Popular Photography 1970-11: Vol 67 Iss 5 p.17


Journal of the SMPTE 1971-05: Vol 80 Iss 5 p.367


PostPosted: Fri Jun 10, 2022 2:37 pm    Post subject: Reply with quote

I found that Evernote archive via https://www.librascopememories.com/


PostPosted: Fri Jun 10, 2022 6:45 pm    Post subject: Reply with quote

Here’s a brochure for the 600mm f1.8
https://librascopememories.com/Librascope_Memories/Product_Literature_files/600mm%20Lens%20-%201973.pdf


PostPosted: Fri Jun 10, 2022 6:55 pm    Post subject: Reply with quote

xaprb wrote:
Here’s a brochure for the 600mm f1.8
https://librascopememories.com/Librascope_Memories/Product_Literature_files/600mm%20Lens%20-%201973.pdf


Ahhh didn't navigate to that part... very interesting. This website seems very well documented.

Will have to see if they patented anything next...


PostPosted: Sat Oct 15, 2022 2:11 am    Post subject: AF-go Contax AX even Vivitar 600/8 is working since Catad. Reply with quote

eggplant wrote:
US $3400 Laugh 1

Just read again and realised the camera is included - but it's a first generation Sony A7.

Even with it included not sure how it's worth this much... then again they are selling projection lenses which go for $99 stuck in helicoids for $400... https://www.ebay.com/itm/FAST-140mm-1-8-lens-for-Pentax-6x7-67-Aero-Ektar-Mamiya-645-GFX-135-165-Cinelux

Out of sheer coincidence I archived a listing for a Librascope 300mm and 500mm that had been going unsold for ages. They eventually came to as low as £150 for the 300mm one- no kidding. Then they sold.

https://archive.ph/zwbrD 300mm
https://archive.ph/zEFfg 500mm

With all that out of the way...


I am curious how you found this evernote website- never heard of it, who shared this?

As for information, I can find this specific model and the others offered as a lens for 35mm SLRs, motion picture and TV cameras in 1970-1971:

The reference is for this:

Industrial Photography 1970-09: Vol 19 Iss 9 p.90


Popular Photography 1970-11: Vol 67 Iss 5 p.17


Journal of the SMPTE 1971-05: Vol 80 Iss 5 p.367

For AF use it on Contax AX even slow F8 vivitar 600/8 cat is working since catadioptic. i tested it.


PostPosted: Sat Oct 15, 2022 9:47 am    Post subject: Reply with quote

What do you mean by "since catadioptric"? Do you mean that optical design has something to do with autofocus capability?

I have some ideas but won't put words in your mouth.