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Pacific Optical 9.4 inch (239mm) f1.0
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PostPosted: Sun May 15, 2022 8:26 pm    Post subject: Pacific Optical 9.4 inch (239mm) f1.0 Reply with quote
No, I am not related to the seller (and no, I don't think they'll get $100,000USD for it)

https://www.ebay.co.uk/itm/294981350096

archived: https://archive.ph/szPHq

Quote:
This is a Pacific Optical Div. of Bournes, Inc. 9.4 inch (approx. 239mm) f1.0 lens with an image circle that is approx. 7-1/2 inch diameter . This Exceptionally Rare (one of the fastest lens ever made in this focal length) lens is believed to have been originally designed for high altitude aerial imaging as it has a front air pressure valve - most likely contracted by the Military for aerial surveillance /reconnaissance uses. This lens has no aperture and can be focused to infinity using a bellows. It offers a Super fast f1.0 aperture creating an Exceptional Background bokeh.

Around the front ring shows, "Pacific Optical Div of Bournes, Inc Low Angeles PN 41300 9.4 inch f/1.0. 12x MFR 93706 SER NO 5361-004 Subcontr NO. AS-786339-AS "

This lens weighs approx. 81 lbs (84lb with both caps)
Lens length: approx. 13-3/4" long
Front barrel diameter; 11" (280mm)
Front glass diameter: approx. 9-3/4" (235mm)
Rear barrel diameter: approx. 9-1/2" (241mm)
Rear glass diameter: approx. 7-1/4" (184mm)
Lens mounting flange - approx. 12" diameter

Using an old Process camera to see what this lens can do, infinity was approx., 9" from front of wood lens board to ground glass of camera.


They've attached 83 photos - I won't upload them all...

Just before getting into them - it's worth noting that the USAF Lens Datasheets (uploaded here https://archive.org/details/USAF_lens_datasheets/01-Section-1) list many fast lenses around this speed and focal length (and faster!) - so it's not unheard of. Particularly because this lens and those lenses were used/made for aerial photography.

I looked through all of those and couldn't find one of these specifications (maybe it was after?).

The general symmetry here makes it to be some sort of Double-Gauss, imo, atleast highly modified.

















PostPosted: Sun May 15, 2022 8:33 pm    Post subject: Reply with quote
Here is the pictures showing "an image circle that is approx. 7-1/2 inch diameter":





Correct me if I'm wrong, but it doesn't look like it's designed to use the whole image circle? Am I seeing high field curvature or high vignetting near the edges, where the depth of field increases quite dramatically.
(Please correct me!)


PostPosted: Sun May 15, 2022 9:13 pm    Post subject: Reply with quote
Looks to be yellowed, indicating thoriated glass, like the Kodak Aero Ektars, so it's no longer f1.0, but a bit slower and will need to be cleared with UV light.

I'd say what you're seeing is field curvature at the edges, more common with wide angle lenses, but pretty common.

You will be able to find out what size negative it used by looking at what cameras were being flown. 3x5" sounds possible/likely, but just a guess, that would require an image circle just under 5", which looks like it would fit inside the area of this lenses's image circle that had good quality.


PostPosted: Sun May 15, 2022 9:53 pm    Post subject: Reply with quote
f being the geometrical aperture, the lens of course remains f1.0 even if the glass is darkening.
The transmission (T) will be reduced, though ...

Similar superfast lenses - although made here in Switzerland - have been used in the Mirage III RS reconnaissance airplanes.
To get an idea what it was about see here at 00:35, 00:52, 1:30-1:50, 2:30, 2:38, 2:46 and 3:00 ...

https://www.youtube.com/watch?v=nGWxxCK71xM (here in the film the Mirage fighter is shown, not the reconnaissance airplane)

Living close to a military airfield, those machines were a common sight directly above our house, often flying as low as 100m (300ft) over hilly ground. Actually some of the footage shown in the film linked above was shot quite close to where I live.

Wonder where those lenses ended up ...

Another "wonderlens" I know to exist at a private collector here in Switzerland is a satellite tracking camera made by Wild Heerbrugg (the same manufacturer as the above mentioned superfast Mirage lenses) in 1952 (!!). Remember the first satellite went into orbit in 1957 only ...

S

Last edited by stevemark on Sun May 15, 2022 10:16 pm; edited 1 time in total


PostPosted: Mon May 16, 2022 7:05 am    Post subject: Reply with quote
I know the owner and we chatted often. Seem sto me that this lens was used for closeup shots, as it has "12x" printed of the front name ring. It was not designed for infnity or normal photography.

Further there is this vent on the side which allows to evacuate the lens, which leads me to believe it was used for scientific imaging at or inside a bubble chamber, where very faint reactions had to be recorded, hence the need for a superfast lens.


PostPosted: Mon May 16, 2022 8:50 am    Post subject: Reply with quote
Interesting, I imagined the pressure valve was somethingto do with changes in air pressure at high altitude in an aircraft, but other aerial lenses don't have such valves.


PostPosted: Mon May 16, 2022 11:33 am    Post subject: Reply with quote
kds315* wrote:
I know the owner and we chatted often. Seem sto me that this lens was used for closeup shots, as it has "12x" printed of the front name ring. It was not designed for infnity or normal photography.

Further there is this vent on the side which allows to evacuate the lens, which leads me to believe it was used for scientific imaging at or inside a bubble chamber, where very faint reactions had to be recorded, hence the need for a superfast lens.


That is interesting- I completely overlooked the 12x marking.

I am not actually sure on the macro interpretation- 12:1 magnification? Seems steep- could you enlighten me? I'm sure the USAF knew what they were doing...

1:12 magnification would mean focusing at 3.36m for a 239mm FL. For the angle of view of this lens, that's pretty far- even if used on 35mm film that would be pretty far.

Sometimes "12x" markings can actually refer to the level of 'magnification' compared to the human eye. 12 x 20mm does come out to 240mm...

Also, lenses made for such high mag closeup work, when used at mid or infinity distances, tend to exhibit pretty horrible aberrations that would be visible on the ground glass.


PostPosted: Tue Jun 07, 2022 2:52 am    Post subject: Reply with quote
If anyone has questions about the lens - I am the owner of it and happy to be of assistance. I would truly love to find out its origin. It is truly one of the most unique lenses that I have EVER come across.

BTW, I am open to offers 😎


PostPosted: Tue Jun 07, 2022 10:11 am    Post subject: Reply with quote
PhotographerLink wrote:
If anyone has questions about the lens - I am the owner of it and happy to be of assistance. I would truly love to find out its origin. It is truly one of the most unique lenses that I have EVER come across.

BTW, I am open to offers 😎


I am actually curious if you could get a large format photographer in the area to take a few photos through it. I'm sure relative to the asking price (or even a cheaper asking price) it would be worth doing, just to see what it looks like... even if it doesn't leave your house.


PostPosted: Tue Jun 07, 2022 10:32 am    Post subject: Reply with quote
I'd first have to buy a boat and learn how to sail the ocean to go pick it up as it exceeds the weight I can take in my luggage. On the bright side I could use it as an anchor if necessary.


PostPosted: Tue Jun 07, 2022 8:57 pm    Post subject: Reply with quote
D1N0 wrote:
I'd first have to buy a boat and learn how to sail the ocean to go pick it up as it exceeds the weight I can take in my luggage. On the bright side I could use it as an anchor if necessary.



She is a Beast indeed but from the "adapted" smaller format imaging I have done has a buttery bokeh and would be exceptional for portraiture and product imaging.

Also to answer a post above, yes, it does hit infinity


PostPosted: Sun Jan 29, 2023 6:07 pm    Post subject: Reply with quote
PhotographerLink wrote:
If anyone has questions about the lens - I am the owner of it and happy to be of assistance. I would truly love to find out its origin. It is truly one of the most unique lenses that I have EVER come across.

BTW, I am open to offers 😎


The listing appears to have vanished, so it was either sold or went unsold and wasn't relisted. There's no Pacific Optical item on their store at the moment anyway, nor in their completed/sold items list.

I wonder who got it... and whether images have been made with it...

This forum would benefit from knowing Smile


PostPosted: Sun Jan 29, 2023 7:25 pm    Post subject: Reply with quote
Maybe contact the owner via PM here: http://forum.mflenses.com/privmsg,mode,post,u,12154.html


PostPosted: Mon Jan 30, 2023 10:06 pm    Post subject: Reply with quote
eggplant wrote:

The listing appears to have vanished, so it was either sold or went unsold and wasn't relisted.


It looks like the lens is always there, just the price tag is cut off considerably.

If you are still looking for a cheaper option from the same maker and you live in the USA (so, you are not condemned to an overweighted shipping fee), here is a gorgeous looking curiosity, Pacific Optical Corporation Xpansa Adjustable, whose appearance makes think about Angenieux projection "zooms" for 35mm. Just an aesthetic off-topic.


PostPosted: Wed Feb 01, 2023 10:23 am    Post subject: Reply with quote
alex ph wrote:
eggplant wrote:

The listing appears to have vanished, so it was either sold or went unsold and wasn't relisted.


It looks like the lens is always there, just the price tag is cut off considerably.

If you are still looking for a cheaper option from the same maker and you live in the USA (so, you are not condemned to an overweighted shipping fee), here is a gorgeous looking curiosity, Pacific Optical Corporation Xpansa Adjustable, whose appearance makes think about Angenieux projection "zooms" for 35mm. Just an aesthetic off-topic.


Oh- I have no idea how I missed that then... EDIT: seems it's one of the few items that don't appear on eBay.co.uk, shipping issue of course...

The Xpansa is in the same category as the ISCO Magna-Com: a zoom attachment sitting infront of a fixed focal length projection lens to let you tweak to different screen sizes, so not light cut off.
It's a negative and positive group. I imagine you'd have to refocus the projection lens after adjusting. Not necessarily meant as a full zoom. The Schneider Variable Prime projection lenses a later thing in the same category. There were also more compact 'versions' ISCO and Schneider made.

The Xpansa dates to the 1950s atleast, and yes- very cool looking Smile

FURTHER EDIT: reminding myself of the 12x text written on it, will probably pass...


PostPosted: Wed Apr 05, 2023 6:23 pm    Post subject: Reply with quote
eggplant wrote:
PhotographerLink wrote:
If anyone has questions about the lens - I am the owner of it and happy to be of assistance. I would truly love to find out its origin. It is truly one of the most unique lenses that I have EVER come across.

BTW, I am open to offers 😎


The listing appears to have vanished, so it was either sold or went unsold and wasn't relisted. There's no Pacific Optical item on their store at the moment anyway, nor in their completed/sold items list.

I wonder who got it... and whether images have been made with it...

This forum would benefit from knowing Smile


This beast is still available and begging for a new home.... If you are local and want to try it... or you are interested in buying it, shoot me an offer...I am motivated Very Happy
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