O_ER Camera Modification

[wombat2go]

I saw this O_ER camera and purchased it because it is a primitive metal box camera similar to the ones I build
as a hobby (see my other thread here)

https://app.box.com/s/xrbusg337r0z7anx886r
https://app.box.com/s/4qqycmklzpot42bzz7h4
https://app.box.com/s/f4vrui54o9egyjwe2xir

The O_ER camera is very solidly built of machined aluminum, the box is of folded and welded Al plate.
and has the Ilex #3 shutter with the
Oscillo-Paragon 1:0.85X ILEX 3 Inch (75mm) f/1.9

and the back is a heavily built Polaroid with no apparent model number , serial C8403750.

The purchase price was a fraction of some prices I saw for just the Oscillo-Paragon lenses.

The camera is in good condition, the lens appears clean except for dirt on the front glass.
The shutter works except it does not latch on B & T, and I have not timed it yet.
The shutter is the "press" type and works with a cable too.

The distance from the centre of the shutter to the film plane is about 150mm; I don't know where the N2 is yet.

I don't think this is an ordinary oscilloscope camera (I used many in the day)
and I assume it may have been a process camera for copy work.

I would be interested to hear if anybody knows about this camera.

I see some negative reports about this lens used as a normal camera, but I will go ahead with a modification anyway.
I am getting good prints up to 17 inch (430mm) from my other medium format cameras and my home C41.

Here is my plan to modify it (I have enough machining and measuring equipment to do it, I think)
Don't hold me to it, am busy, not fully retired yet, , it might take me a year or two!

1. Clean the lens and shutter
2. Check calibration of the shutter timing.
3. Cut the box length back to infinity focus for the lens
4. Make a back for the Graflex RH/10 ( I have done that before)
5. Modify the unusual but solid lens external structure for focussing and limited tilt movement.
6. Escape route: if the lens is no good for general work, I can replace it with a better lens.

Any comments will be appreciated.

 

[Dan Fromm]

Meandering marsupial, it smells like a 'scope camera. The Oscillo-Paragon and similar lenses from Wollensak and other makers were all made for use in oscilloscope cameras, should have been designed to image the curved front of a cathode ray tube on a flat sheet of film. I don't know whether they actually were.

When used for general photography, the lenses get mixed reviews. The consensus of LF photographers is that they don't cover 4x5 at infinity and are unacceptably soft at infinity at all apertures. Some, not all, like them for use closeup. And tiny-chip digicam users like them. I have a few, wouldn't use any of them. I like to think I'm venturesome, but I'm not that venturesome.

I can't see how the lens is mounted to the box. I've extracted Oscillo-Paragon lenses in self-cocking and "electronic" Ilex shutters from 'scope cameras. The self-cocking shutters all came from Tektronix cameras, none had rear mounting threads. You'll find out when you dismantle it.

You have the tools, the know-how, and the time. Go to it. I'd run away but I'm not you. If I were to do anything with it, I'd toss the lens, shutter and all, and try to adapt the box for use with a 150 mm +/- lens.

Re tossing the shutter, 75/1.9 Oscillo-Paragons are in Ilex #3s with restricted diaphragms. Between that and the lack of mounting threads, making the shutter usable with a lens made to fit an Ilex #3 seems more trouble than its worth. For me, not necessarily for you.

Cheers,

Dan

 

[wombat2go]

Hi, Dan,
I am looking to use this on the RH/10, not 4 x 5
What was the frame size of the Polaroid back on this camera? It looks like something less than 70mm high,

After WW2 the oscilloscopes became measuring instruments with a demand for accuracy across the field.
I have an old Eico TR 410, from early 1960's I think, and I just pulled the front reticles off it.
The front of the tube is flat by a straight edge and I can't measure the phosphor, of course, but visually it is fairly flat too, right out to the periphery.
In digital and analog electronics in 1970's we trusted the oscilloscopes above all else, and the timing measurements were taken after the triggering on the far left of the screen, and blowing up the timebase as far as possible to the right.

However I understand that a 75mm lens designed to focus at 150mm will not be optimised for infinity, but I am interested to see how it works,and its artifacts; most of my medium format photos are outdoors with Fuji 400 C41, stopped down F/11 to f/16.

On the Ilex #3 in this camera the diaphragm opens right out of the bore when opened below the f/1.9 on the scale
The scale is f/1.9 to f/16.
Thanks for the comments and regards,

edit: Also the oscilloscopes cameras of the day had to focus sharply on the reticle which was invariably flat, in my experience, so the often mentioned curved field of these lenses is probably from the internet myth repository / regards

 

[Dan Fromm]

MM, is it possible that 'scope CRTs' inner front surfaces, where the phosphors are, are curved? I've used Tek and HP scopes, and now that I think of it their CRTs front surfaces were flat.

Interesting that y'r lens' Ilex' diaphragm opens fully. Mine don't. There are no rules in Rochester, and no one follows them.

 

[wombat2go]

Karl Ferdinand Braun, invented the cathode ray oscilloscope in 1897. I wonder when they started using cameras on them?

http://www.crtsite.com/oscilloscope crt.html
Some pictures of scope tubes. The early 1930's ones were sometimes flat, sometimes bulbous and of about 3 inch diameter , into 1950's ~ 70's Tektronix etc were flat ( toward the bottom of the page)

Here is an Oscillo -Raptar on a 1962 scope camera in HP's virtual museum. I presume from the chronology page on the site that it is the earliest HP scope camera
http://www.hp.com/hpinfo/abouthp/histnfacts/museum/imagingprinting/0013/0013front.html
Lens looks rather similar to the offending Ilex one.

 

[wombat2go]

Supposed the be half retired, I spent too long on the day job and got back from Korea.
Incidentally I took Ricoh KR-5 35mm slr on the trip because I am not confident my home brew medium format cameras would make it through the airport security checks without drama etc.

The O_ER camera is now in pieces,
The Ilex Nr 3X Universal Ilex Oscillo Paragon shutter was not working properly so I opened it up.
The clockwork is of plated heavy duty gears still brightly polished so I left them untouched.

The problem was on the other side around the press shutter lever . It seems to have wear from use.
Also the cam plate shows signs of wear and the original bright blue lube has dried.
The secondary levers for B & T were not moving consistently.
I applied Radio Shack Cleaner & Lubricant >Tetrafluroetano + Aciete mineral blanco
just to the rubbing surfaces around the shutter release pivot.
On re-assembly the shutter is now working , but I have yet to calibrate the timing.

In rebuild to see if the lens works as a camera lens, I will try to use as much of the original O_ER camera as possible.
This will entail some machining, both in the inversion of the macro lens/shutter combo and in the replacement
of the Polaroid back with a RH/10

Below is the rudimentary lens bench where the shutter and the lens will be tested.

 

[wombat2go]

Today the Ilex shutter and Oscillo lens were set up in the crude medium format lens bench.
The lens was reversed compared to its original orientation.
Shutter speeds are not too bad:
Speed Setting Specified millisec Actual millisec
100 10 10
50 20 22
25 40 45
10 100 144
5 200 270
2 500 700
1 1000 1100 ~1200

The lens appears to have a focal length of 75mm with the N2 plane about in the middle of the shutter.
The image circle is about 80mm dia from f/1.9 to f/22.
The nearest data I found on the lens was for the Elgeet Oscillo Navitar 76mm f/1.9
Probably the same lens as this Ilex one.
It is a modified symmetrical (Speed Panchro) shown as Diagram S5 in Arthur Cox, page 485.
The inner surfaces of each half of the lens are both very close to the diaphagm when the lens is assembled.

 

[AgX]

Karl Ferdinand Braun, invented the cathode ray oscilloscope in 1897. I wonder when they started using cameras on them?

Braun did not invent the cathode ray oscilloskop, "just" that tube. It took about 35 years to arrive at a commercial oscilloscope. Nevertheless an interesting question.

 

[wombat2go]

Progress on the Oscillo Lens
Some internet search indicated that these 75mm f/1.9 lenses have a bad reputation as camera lenses.
Comments that the lens is a "doorstop" or "paperweight" without examples.
Comments that the Oscillo lenses were somehow designed for curved cathode ray tubes, I could not find that this could have been done on a speed panchro with spherics, or why, given that cro tubes were mostly flat screens in USA when this lens was used.

A few examples of actual photos, and of those, most are with cardboard and tape style adaptors; the lens opened wide for portraits with the artifact of blurred outers.

After some messing around with the lens bench, I went ahead and reversed the lens in its mount.
That involved the " corn cob and vodka " method.
The gas grill is in the workshop for the winter, and of course I would never drink vodka in the workshop!
Using the existing parts, the adaptor ring was re-bored on the lathe for the other end of the lens, with a clearance of + 0.003 inch.
The OD of the adaptor ring was then reduced to 3.200 inch
After some calculation and guessing, the lens board was re-bored to an interference of 0.008 inch on diameter, with a 10 degree taper on the lead in.
The ring was soaked in vodka and ice, and the lens board had to endure being heated to about corn cob ~200+ degrees Fahrenheit on the gas grill.

Working fast, with gloves, a smear of Loctite 271 was applied and the lens board was pressed home on to that big lens adaptor.
Then the lens was attached to the lens board in reverse, by the existing optical nut.

https://app.box.com/s/mlt5m6fwiizqp1h80v78

 

[Dan Fromm]

WW, I looked at the picture you posted. Is that the lens "before"? I ask because it shows the lens with the trim ring out. Perhaps I misunderstood what you did.

 

[wombat2go]

Good Morning, Dan
That photo is with the lens newly modified, that is, reversed from its original orientation.
Note that the "lens board" was , and will be, in front of the lens, as shown in the photo of the original camera.
Originally the nameplate end of the lens was attached to the lens board.
With my mod, the nameplate end of the lens will point to the film.

With search in my spare time, I found a generic prescription for the speed panchro ( 6 glass, double gauss)
I am modeling that in OpticalRayTracer. Of course I don't know if the model is the same as the Oscillo.
But the focal length is 77mm and the dimensions are close to what I can measure on the real Oscillo

Still working on it, but so far it seems that the lens would need to be reversed to cover the original Polaroid at 1:1 .
When the reversed lens is focussed on infinity the spherical abberation is bad., but the image circle is more than 100mm at 1:1

When I flip the lens model to its correct orientation the image circle reduces to about 38mm radius (76mm dia)
Then the spherical is well corrected ( within 200 micrometre or so) from the film plane, between axis and 38mm radius.

So that leads me to wonder if the Oscillos lens was just a variant of a standard Speed Panchro medium format lens, but reversed in the shutter by swapping the shutter threads between front and rear .
Do you think that is feasible?

 

[Dan Fromm]

Small surprise of the day. I have a set of 75/1.9 Oscillo-Paragon cells -- actually, I have two of 'em -- and several Ilex #3 shutters. So I did the obvious thing, tried to screw a rear cell into the front of the shutter. It won't go, hits the diaphragm before the threads engage. So much for that.

Speed Pancho is a TTH trade name that includes a number of different prescriptons, all 6/4 double Gauss types. I refer to the type as 6/4 double Gauss to avoid pointing at a particular and very good lens. There are many, many 6/4 double Gauss type lenses, some better than others.

 

[wombat2go]

Progress on this thread (Its a spare time thing):
I have made a "flying test bed" 6x7 body out of the old O_ER camera parts, it is "thin" as suggested by Dan Fromm.
So there is plenty of room up front to mount experimental lenses on a machined adaptor plate set up.

Here is a raw image with the Oscillo lens on Fuji 160. .... Yikes.
https://app.box.com/s/4tnhnaytrml2vtfpbxxg

It does not quite cover the 6x7. But worse , it has severe pincushion.
With some reading and using Imagemagick functions , I think the distortion is of the third order with radius. So the distortion is not so obvious near the axis but gets bad at the edges because it grows with 3rd power of radius
Here is the above image that has been partially corrected for 3rd order distortion by "convert" function and tca by "tca_correct" , and cropped to 5x5 square. ......But still Yikes.
https://app.box.com/s/gl0zrlu7aohiwdj8k395

There is nothing more I can do with the Oscillo so I pulled it off and now making an adaptor for a Takumar 6x7 bayonet, as I have the Taks 6x7 55, 75, & 90mm.

That brings me to the old Ilex #3 shutter.
It had a lot of wear in the hole that mounts the firing lever on its spindle.
I can't imagine how a manual Polaroid camera could have a worn shutter.
I have corrected the problem with an M3 washer so the shutter works and later I will drill the lever and make a brass bush in the lathe to fix it.
The other parts of the shutter look clean and in good shape, and the timing is reasonably OK.

The shutter will have to be reverse mounted to just clear the image cone of the Takumar lenses.

I will put up some photos when( and if !!) it is working OK.

regards,

 

[Dan Fromm]

Wombat, thanks for the update. Thanks too for confirmation that 'scope camera lenses aren't the answer to an aging photographer's prayers.

Cheers,

Dan

 

[wombat2go]

Thanks Dan,
I have learned that the "lens bench" approach is no way to test a lens.
For testing a lens there is no substitute but for taking a real photo with the lens properly aligned and light tight