1800mm and Beyond

[Hermes07]

Would really like some opinions on this.

I've always wanted to experiment with long lenses, REALLY long. I have plenty of bellows but 70" is, as far as I know, the longest focal length manufactured commercially. The only lenses I can find longer than this are achromats designed for use as telescope objectives e.g. - http://www.intane-optics.com/products/achromatic-220mm-f-12-56-catalog-1.html

Would these be any use whatsoever as taking lenses (for colour or orthochromatic processes?)

Does anyone have any experience as to the sharpness of these lenses wide open or stopped down? Any notion of the sort of useful coverage they'd give for positives that will be directly viewed or contact printed?

Sorry for asking such vague questions - hopefully someone who has once tried a lens of this type for large or ultra-large format photography will be able to chime in and educate me a little.

[Dan Fromm]

Boyer made a handful of 2500/12.5 Apo Saphirs. Most of them were bought by the French Atomic Energy Commission.

I have an Apo-Saphir catalog with a copy of a letter dated October 27, 1965 from the director of the Central Arms Laboratory in which he states that the lab has just received 53 Apo Saphirs, focal lengths 300, 450, 600, 900, 1200 and 2500 mm. He says that they fully met specifications, in particular in respect to resolution, air- and water-tightness, and corrosion resistance. I believe these lenses were used to photograph A-tests.

There's a picture of 14 2500/12.5 Apo-Saphirs in the catalog. The catalog was issued while Andre Levy owned Boyer. Eric Beltrando tells me that he saw a batch of 8 2500/12.5s at CEDIS-Boyer some years after control of the firm passed to CEDIS. AFAIK most of the Apo-Saphirs that went to Mururoa are still there.

These are 30 degree lenses, cover 1340 mm.

USAF bought 96"/8 and 144"/8 lenses from Perkin Elmer. I think you have as good a chance of finding one of them as of finding a 2500 Apo-Saphir.

You might want to look at the 1963 GOI lens catalog. It lists Soviet lenses known to the State Optical Institute up to that date and includes some monstrous lenses for aerial cameras. You can download it from http://www.lallement.com/pictures/files.htm More unobtanium, I'm afraid.

[Hermes07]

Thanks for the information Dan.

I had read a little about about the 2500mm Apo Saphir (I believe in an article you authored) - but never thought I had much chance of actually finding one for sale.

Fear the same might be said for the soviet lenses.

My Russian is rusty and my French is even worse - I'll will try both avenues on the chance that they will turn up a lens of this size but I'm not holding my breath. I seem to recall reading that there was only 1 of each made of the Perkin Elmers you mentioned so they're pretty-much out of the picture if that's the case.

The rarity of these lenses is what's driven me to consider the achromats. The trouble is that I have no idea how they'd perform as taking lenses. If it came to it I could try using two of the large achromats with a negative element in between to improve the quality in a cooke triplet kind of design, but if it's going to produce completely unusable results I'd much rather not spend a grand attempting it.

[Dan Fromm]

You're pretty much in refracting telescope territory, might want to look for places where users discuss them.

You might also find this http://alag3.mfa.kfki.hu/astro/giantlenses/200mm.htm site interesting. All sorts of odd stuff there, including leads to manufacturers.

[johnielvis]

I posted before about rolyn optics...


they have these lenses nos

not cheap likely, but new

rolyn.com

[Photomagica]

Have a looks at Surplus Shed as well for Achromats.
http://www.surplusshed.com/pages/category/objectivelenses_3.html

Achromats are very sharp on axis - typically diffraction limited. They deteriorate rapidly off-axis but might perform very well if your film isn't too large.

Bill Peters
Photomagica

[Hermes07]

Thanks for the links but I've tried all those sites in the past. Rolyn do not have any of the 2500mm Apo Saphir despite what their site says.

Have found plenty of sources for the achromats. Trouble is, all the reviews/discussions are about using them in telescopes with eyepieces which is very different from using them to cover a large sheet of film or paper. Ideally Id want a 2400mm lens with 25 degrees of coverage and a 4000-5000mm lens with 12 degrees of coverage. Anyone have any idea what I'd get if I tried to use an achromat to get those sorts of numbers, Usable? Usable if stopped down a lot? or complete waste of time?

[GPS]

...
Have found plenty of sources for the achromats. Trouble is, all the reviews/discussions are about using them in telescopes with eyepieces which is very different from using them to cover a large sheet of film or paper. Ideally Id want a 2400mm lens with 25 degrees of coverage and a 4000-5000mm lens with 12 degrees of coverage. Anyone have any idea what I'd get if I tried to use an achromat to get those sorts of numbers, Usable? Usable if stopped down a lot? or complete waste of time?

Hermes, do yourself a favour and come to your senses. The achromats you talk about are lenses that focus an image to an eyepiece. How on Earth could they cover a LF film (much more then ULF you speak about in your first post)? The film is even bigger than the diameter of the lens!

[Hermes07]

Are you suggesting that one of these lenses will only illuminate an image circle of a few centimeters/inches? That's contrary to my basic experience with other small achromats which have all illuminated big circles.

If you're suggesting that they will illuminate but be totally unusable outside the dead centre of the image circle then please, share your experiences in more detail. Will they still be unusable at f/32?, at f/128? What angle can they cover sharply before their performance drops off?

[E. von Hoegh]

Are you suggesting that one of these lenses will only illuminate an image circle of a few centimeters/inches? That's contrary to my basic experience with other small achromats which have all illuminated big circles.

If you're suggesting that they will illuminate but be totally unusable outside the dead centre of the image circle then please, share your experiences in more detail. Will they still be unusable at f/32?, at f/128? What angle can they cover sharply before their performance drops off?

They will illuminate quite a large circle, but their sharp coverage is limited to a few degrees - by a few I mean 3 to 4, if that. You could check out the telescope oriented site mentioned above, they will have the coverage info you want. You should calculate the angle of sharp coverage you need from each focal length and work from there. I don't think you mentioned what format you will use. If 35mm, those telescope achromats might be surprisingly good if well baffled. But keep in mind that they are designed to focus an image on an eyepiece (as mentioned above) with a diameter of what, an inch??

Edit: You know a pair of achromats with a central stop make a rapid rectilinear type lens, right?

[GPS]

Are you suggesting that one of these lenses will only illuminate an image circle of a few centimeters/inches? That's contrary to my basic experience with other small achromats which have all illuminated big circles.

If you're suggesting that they will illuminate but be totally unusable outside the dead centre of the image circle then please, share your experiences in more detail. Will they still be unusable at f/32?, at f/128? What angle can they cover sharply before their performance drops off?

I see, you're experienced... Now, when you have the experience with "illuminated big circles" "please, share your experiences in more detail". What size of film "can they cover sharply before their performance drops off?" ;)

[Hermes07]

I have only seen the image circle by eye. Not the same as inspecting a negative shot by one and it definitely doesn't make me experienced or an expert.

[GPS]

Well, the truth is that these lenses cannot be used as an equivalent of a LF long focal lens.

[johnielvis]

OH well....the guy there led me to believe they had them at rolyn

I was also considering telescope lenses--saw a few long "telestigmats" for auction and was considering.....looks like that's the only option now that's do-able if you want LONG...

that or custom made---perhaps edmund? for custom made? Idon't know how big they go but they do have pretty big optical flats available....maybe they can make an artar type 4 element--symmetrical---that's simple design I'm thinking...so maybe not out of the world expensive....I was going to ask them "one of these days"...but the 1200 I got is plenty big for now....

[Hermes07]

They will illuminate quite a large circle, but their sharp coverage is limited to a few degrees - by a few I mean 3 to 4, if that. You could check out the telescope oriented site mentioned above, they will have the coverage info you want. You should calculate the angle of sharp coverage you need from each focal length and work from there. I don't think you mentioned what format you will use. If 35mm, those telescope achromats might be surprisingly good if well baffled. But keep in mind that they are designed to focus an image on an eyepiece (as mentioned above) with a diameter of what, an inch??

Edit: You know a pair of achromats with a central stop make a rapid rectilinear type lens, right?

Thanks, this is largely what I wanted to know. By the look of it, with 3 or 4 degrees sharp coverage I could perhaps get something usable on 8x10 at 1:1 with a very long lens (3000mm-4000mm) but that would obviously be limiting.

The trouble with the two-achromat rapid rectilinear is that I'd end up with basically half the focal length of the individual achromats. The effective focal length would be around 1200mm-1500mm which I already have covered with process lenses. I was thinking of two achromats with a negative element in between like a cooke triplet - the negative element allowing me to achieve longer focal lengths. Definitely not confident enough to spend a thousand dollars to try it out yet though.

[Hermes07]

OH well....the guy there led me to believe they had them at rolyn

I was also considering telescope lenses--saw a few long "telestigmats" for auction and was considering.....looks like that's the only option now that's do-able if you want LONG...

that or custom made---perhaps edmund? for custom made? Idon't know how big they go but they do have pretty big optical flats available....maybe they can make an artar type 4 element--symmetrical---that's simple design I'm thinking...so maybe not out of the world expensive....I was going to ask them "one of these days"...but the 1200 I got is plenty big for now....

Can't say anything for sure, but I emailed Rolyn and they told me they didn't stock the 2500mm. Did you hear something different?

Would definitely be interested if there was an attempt to get some longer lenses manufactured but I doubt it will be affordable enough to bankroll single-handedly.

Perhaps I'm in the "a little knowledge is a dangerous thing" category but I still feel there must be a way to get usable results from the achromats. They'e already being mass produced in long focal lengths, are coated and are relatively affordable. If using them on their own won't yield good enough results then a simple way to combine them in a better-corrected compound lens must be possible.

[E. von Hoegh]

Thanks, this is largely what I wanted to know. By the look of it, with 3 or 4 degrees sharp coverage I could perhaps get something usable on 8x10 at 1:1 with a very long lens (3000mm-4000mm) but that would obviously be limiting.

The trouble with the two-achromat rapid rectilinear is that I'd end up with basically half the focal length of the individual achromats. The effective focal length would be around 1200mm-1500mm which I already have covered with process lenses. I was thinking of two achromats with a negative element in between like a cooke triplet - the negative element allowing me to achieve longer focal lengths. Definitely not confident enough to spend a thousand dollars to try it out yet though.

You could try the Cooke triplet idea with two shorter (read cheaper) achromats from say the Surplusshed.com, combining them with a cheap negative lens from the same source. Should give at least a proof of concept, and the design should scale. Cooke triplets were pretty good, too:) .

[Hermes07]

You could try the Cooke triplet idea with two shorter (read cheaper) achromats from say the Surplusshed.com, combining them with a cheap negative lens from the same source. Should give at least a proof of concept, and the design should scale. Cooke triplets were pretty good, too:) .

Thanks for the advice.

The hardest practical bit of trying a design like this is finding the negative lenses in large enough diameters to keep an overall respectable aperture (I want to test a design I can actually make at full scale). You're basically stuck taking the negative lens you've managed to find as a starting point, and then trying to work backwards to the focal length you want.

I think the best formula I've come up with that I could actually make is two 1200mm achromats with a -800mm negative in the middle. Should give a focal length in the 2200mm-2300mm range.

Am ordering two 120mm achromats and a -80mm negative meniscus as we speak for a nice 1/10 scale attempt :)

[johnielvis]

he didn't SAY he had them, but he did kind of say they have everything on the website...he had the pentac 8" nos.....that was a while ago.

anyways--I bought a trial lens set (optician).....that's a way if you don't mind 1" diameter lenses---you can get positive and negative coated fractional diopter high quality glass that way---I just got the single, uncoated set and was experimenting with LONG fl's---2 element combinations---one positive, one negative---work pretty good....they're already at tiny apertures though....so you'll shoot "wide open"....the chinese trial lens sets are pretty reasonable--anything bought in usa requires an opticians license and millioins of dollars---getoptic is the name of the place I got the trial lens set from....china, but they delivered--no ripoff....took a while--had to do a wire xfer to get them the money...what a pain that is...AVOID wire xfer!!!!

I got diopters starting at .25---that's 4!!!!! metres focal length!!!!

[Jim Michael]

I'm curious how a zone plate would perform at a very long focal distance.

[Hermes07]

he didn't SAY he had them, but he did kind of say they have everything on the website...he had the pentac 8" nos.....that was a while ago.

anyways--I bought a trial lens set (optician).....that's a way if you don't mind 1" diameter lenses---you can get positive and negative coated fractional diopter high quality glass that way---I just got the single, uncoated set and was experimenting with LONG fl's---2 element combinations---one positive, one negative---work pretty good....they're already at tiny apertures though....so you'll shoot "wide open"....the chinese trial lens sets are pretty reasonable--anything bought in usa requires an opticians license and millioins of dollars---getoptic is the name of the place I got the trial lens set from....china, but they delivered--no ripoff....took a while--had to do a wire xfer to get them the money...what a pain that is...AVOID wire xfer!!!!

I got diopters starting at .25---that's 4!!!!! metres focal length!!!!

Isn't composing/focusing at f/160 kind of difficult?

I'm trying to keep as large a diameter as possible given how low the ISOs I have to use are. Also looking at ordering from China but much larger optics, Barride seem to be the cheapest with good response to emails.

The two focal lengths I'd really love are 2400mm and 4800mm. Would need 24 Degrees coverage at 2400mm and 12 degrees at 4800mm. In theory both could be done with a triplet using two 1200mm achromats and different negative elements in the middle.

[Armin Seeholzer]

Hi in Vevey in the camera museum is a 3m / 3000mm lens from the swiss army but its only f 50 if I remember correctly its about 1,6m long and is in a box!

Cheers Armin

[Dan Fromm]

he didn't SAY he had them, but he did kind of say they have everything on the website...he had the pentac 8" nos.....that was a while ago.

Stuff and nonsense. Some years ago my wife authorized me to buy Rolyn's stock of Boyer lenses if the price was right. I discussed this with John Ross. Not much stock -- most of the items listed on the site were long gone -- and in the end the price was very wrong.

[Hermes07]

I suspected as much Dan, their list of lenses stocked is suspiciously complete and comprehensive for optics that are supposed to be discontinued.

[E. von Hoegh]

Thanks for the advice.

The hardest practical bit of trying a design like this is finding the negative lenses in large enough diameters to keep an overall respectable aperture (I want to test a design I can actually make at full scale). You're basically stuck taking the negative lens you've managed to find as a starting point, and then trying to work backwards to the focal length you want.

I think the best formula I've come up with that I could actually make is two 1200mm achromats with a -800mm negative in the middle. Should give a focal length in the 2200mm-2300mm range.

Am ordering two 120mm achromats and a -80mm negative meniscus as we speak for a nice 1/10 scale attempt :)

Some years ago I looked into making my own RR lens in the 600mm range, for use on 8x10. I found some suitable coated telescope achromats, very reasonably priced, at Surplusshed, then filed the idea on the back burner due to money issues. Later I decided to do it, and lo, they no longer had the lenses. I had visions of a nicely brass mounted lens in an old Compound... oh well. I never thought of a Cooke triplet. Now I am.... thanks.;)

Keep us posted on your project.

[cuypers1807]

Consider making a camera like Andreas Feiniger. He shot amazing photos of NYC from New Jersey. Here is a link to two parts of an interview in which he discusses shooting NYC with a 40 inch lens.

Part 2 - http://www.youtube.com/watch?v=7Iby7p7BN-k
Part 3 - http://www.youtube.com/watch?v=FTFF_FUP33U&feature=related

[Steve M Hostetter]

I remember seeing a 2400mm mounted to a Sinar P on an optical bench of sorts near the front cover of a sinar catalog... The lens had two standards, one at both ends..

[Hermes07]

Thanks. Will watch it when I'm back in London with a decent internet connection.

My camera and bellows setup is actually sorted already. Will have more than enough extension to shoot with a 4800mm. Would be using it indoors so at least I won't have to battle with the wind.

[Hermes07]

Steve. Don't keep me in suspense - name that lens!

[Steve M Hostetter]

Hermes,

More then likley I'd say it had a sinar brand being it was in their catalog so maybe one of the Rodenstock lenses I really can't say..

[Maris Rusis]

I regularly synthesise very long focal length lenses by using Gullstrand's Equation. My application is to turn big rooms into camera obscuras. My most used lenses are 75mm diameter spectacle lenses from the local optometrist. They cost $20 each.

By putting a +3 dioptre lens in contact with a -3 dioptre lens the powers cancel and the focal length is infinite. If the lenses are moved 5mm apart a positive power appears equivalent to a lens of about 22 metre focal length. 20mm apart the combination delivers about 5 metres focal length. In practice adjusting the spacing matches the focal length to the dimensions of the room.

Optical quality is surprisingly good because the extremely large focal ratios (f numbers) tend to minimise aberrations. Image brightness is startlingly when seen by dark adapted eyes. The original camera obscura design using a pinhole is dim and fuzzy in comparison.

[Hermes07]

Interesting stuff Maris - the first I've heard of anyone putting this theory into practice in their work. 75mm diameter isn't too shabby either - if I had a camera obscura setup I'd definitely give this a try.

Do you shoot colour with this setup?

[Maris Rusis]

The super-long focal length combinations are just for "lookers"; rooms that demonstrate the camera obscura phenomenon. I haven't exposed film or paper in these set-ups.