Jmagon vs Imagon

[cyberjunkie]

A question for those with a solid knowledge of vintage german lenses.
Is there any difference between the modern Imagon, made in barrel and sometimes in shutter, with focals from 120mm to 480mm, and the older pre-war Jmagon, with focal expressed in cm., with slightly different easthetics, but with the familiar diffusion disk?

There are very few documents about vintage Rodenstock lenses on the Web, but atleast i could find something about the original Imagon. I understand that it was conceived by Dr. Staeble, supposedly the same one who opened his own lens factory later on, but i didn't find some many useful informations. For example i couldn't find anything about the developement of the Imagon, if it was updated at some point, or left untouched. Being a soft focus optic, very simple (glasses behind the shutter/diaphragm, and diffusion disk/grey filter in the front), i wouldn't be very suprised if the design did actually change very little over time, or none at all.


I have found a decently priced Rodenstock Jmagon 30cm. in barrel, with just ONE disk fitted on the front of the lens. The single diffusion disk reports H=5.8 and H=7.7, probably the values refer to the aperture with and without the disk, and not to the two different positions available with the disks used on modern Imagons.
But it's just my guess. I don't know the Imagon and i have never seen one in use.
I'd be very happy to learn something about the lens, and understand how it compares with its more modern siblings.
Any clue?

have fun


CJ

[Mark Sawyer]

I've heard that the Imagon was redesigned early on, but don't know for sure. Hopefully, Bob Salomon will chime in...

A couple of differences that came later were coatings after WWII, and a more constricted maximum aperture in the 300mm when it went from a Compound/Compur Shutter to a Copal. It went from h/5.8 to h/6.8. (The old Imagon 300mm is actually about f/5 wide open, no disk; I'm not sure what the Copal 3 version opens up to.)

Oh, and it was Dr. Heinrich Kuhn who conceived and developed the Imagon; Staeble first manufactured it.

[Armin Seeholzer]

Its Heinrich Kühn not Kuhn by the way;--)))
He was also a Photographer:
http://www.hatjecantz.de/controller.php?cmd=detail&titzif=00002568

Cheers Armin

[cowanw]

I have found a decently priced Rodenstock Jmagon 30cm. in barrel, with just ONE disk fitted on the front of the lens. The single diffusion disk reports H=5.8 and H=7.7, probably the values refer to the aperture with and without the disk, and not to the two different positions available with the disks used on modern Imagons.

have fun
CJ
I expect you will find the disk has an open and closed position. I have found it is easier to move the ring when it is on the lens. It is not quite as intuitive when off the lens.
While the H numbers are not quite the same as F numbers, they are used as such. H=5.8 for with the small openings open and H=7.7 with the centre hole only.
Without the rings, the lens is about F4.5. Mine came in shutter without f numbers (as is usual) but a previous owner incribed the appropriate fstop numbers on the blank plate.
As there is only one lens behind the shutter measuring the diameter of the glass is easy and you can figure the f stop from there.
Regards
Bill

[Bob Salomon]

The 300mm was reduced in speed and number of disks when it was put into a #3 shutter since the opening in the shutter was too small and didn't allow full opening of the lens. The same thing happens with the 360mm Apo Sironar N and S type lenses and longer.

The 300 Imagon in shutter over the last decades of its life was delivered with 2 disks, a grey filter and a lens hood. Smaller Imagons of the same period came with 3 disks, a grey filter and the hood.

We still do have each of those 300mm disks left in stock; 7.7 to 9.5 and 9.5 to 11.5. Actually we have two of the 7.7 to 9.5 disks and one of the 9.5 to 11.5 disks.

[cowanw]

I think the answer to your question might be a possible maybe. The Imagons I have seen have 2 strong and one weak reflection.
I have just seen a 4.8 cm Jmagon (uncoated) and it has 2 strong (One very large and one small) and 2 small weak but distinct reflections, not counting the filter. It came with a yellow filter placed from behind in front of the diffusion disc, not from the front. The medium yellow filter (8) is not really a 2 X filter like the green or grey filters seen later.
Maybe one of the lens experts can intepret this.
Maybe the modern coatings just make one of the weak relections invisible.
Regards
Bil
PS it is supposed to be an cemented Achromatic Doublet.

[jackpie]

Bob, do you have any disks for the 250mm Imagon?

[cyberjunkie]

In the end i decided to buy the lens :D
Now i have payed for it, so i can post a picture.
There is only one diffusion disk, no yellow (or 2x) filter, and no shade. Maybe the latter accessory is not needed, as the shape of the lens itself provide some shade to the glass.
The name Jmagon (with "J" instead of "I", as used in other pre-war germa lenses) and the focal expressed in cm. made me think that the lens could be made in the thirties, but i didn't find any catalog or advertising material confirming my guess.
I have sent a PM to Bob Salomon asking for the diameter of the Imagon 300mm accessories that are still in stock. As soon as i get the lens i'll check for the front thread diameter.

I have no experience with modern Imagons, and i don't know how the advertised speed of the lens is calculated, but the attached picture shows that the same speed is reported on both the lens and the diffusion disk. The disk has two "H" values, probably because, like with recent Imagons, there are two positions.
Nevertheless, the faster speed of the disk is the same as the speed reported on the lens, and that makes me think that Rodenstock chose to disregard the speed of the objective without disks, implying that the correct use of the lens was WITH disks, and NOT WITHOUT.
Clearly it's just my guess, i'd like to get a conclusive answer from those with first-hand experience (a scan of the accompaying papers would be more than welcome!).
I did a quick reading of "The Plastic Depth Lens "Imagon" by Heinrich Kuhn"
http://www.cameraeccentric.com/html/info/imagon_2.html
Cameraeccentric is too good to be true :D but i found no references in the text to the use of the lens without "diaphragms" (as the diffusion disks are called).
AFAIK the optic used in the Imagon is made by a two elements/one group lens (i.e. an achromatic doublet), like for example a Grubb or Waterbury landscape lens, that many forum partecipants use with great satisfaction.
BTW, at least 9 out of 10 landscape lenses get sold for much more than what i payed my poor old Jmagon. Probably it's just the collector's value, but something still escapes my consideration.
Waiting for your opinion, and back to the original question, i think i can summarize everything in a short line:
why Rodenstock didn't provide the speed for the lens alone?
I understand that a landscape lens is almost unusable with no stop, but many use them unstopped these days, as soft focus lenses. If it's acceptable today, why it wasn't back then, with a lens that was openly described as a soft focus one?
I know, i know, my question is a little bit naive, but i don't see it as meaningless.

have fun


CJ

[Bob Salomon]

"Nevertheless, the faster speed of the disk is the same as the speed reported on the lens, and that makes me think that Rodenstock chose to disregard the speed of the objective without disks, implying that the correct use of the lens was WITH disks, and NOT WITHOUT."

NO! The lens can be used with or without the disk. The speed is the same when used with your disk with all holes open. But without the disk there will be more softness (halation). The total amount of halation will depend on the type of lighting you use and the lighting ratio.

[Armin Seeholzer]

NO! The lens can be used with or without the disk. The speed is the same when used with your disk with all holes open. But without the disk there will be more softness (halation). The total amount of halation will depend on the type of lighting you use and the lighting ratio.

I measured on my 250mm Imagon the div. between the 5,8 and the the opening without the Disc and I got to f 4,5 on my Bron FCMII meter with probe!
Its also physically totaly unrealistic what you say thad it would be the same!
This will also on a 300/360/480 give different f or H stops!

Cheers Armin

[Bob Salomon]

I measured on my 250mm Imagon the div. between the 5,8 and the the opening without the Disc and I got to f 4,5 on my Bron FCMII meter with probe!
Its also physically totaly unrealistic what you say thad it would be the same!
This will also on a 300/360/480 give different f or H stops!

Cheers Armin

But they are the same exposure according to the Imagon instruction book from Rodenstock. Perhapos they measure H stops differently then your meter measures F stops.

[Mark Sawyer]

I've used the Imagon 300mm for quite a few years, and I understand the basic math...

Without any disks, in the #5 Compound, it's an f/4.8. I use the lens without the disks, but with the conventional diaphragm in the compound shutter. It works wonderfully. I have no doubt the Imagon worked wonderfully well with the h/stop diaphragms. The two different wonderfuls are slightly (and only very slightly) different. It's all good!

You could spend a dozen lifetimes playing with the Imagon, and just be getting started... But that's like most lenses...

[cyberjunkie]

I've used the Imagon 300mm for quite a few years, and I understand the basic math...

Without any disks, in the #5 Compound, it's an f/4.8


Thanks for the informations.
Do you know if the lens cell can be easily transferred from the barrel version to a Compound No.5?
I can't try myself because i don't have a No.5, just No.4 and No.3.
Even on a lucky day, their big brother won't come cheap, so better make sure before starting to look for one :D

have fun


CJ

[Bob Salomon]

I've used the Imagon 300mm for quite a few years, and I understand the basic math...

Without any disks, in the #5 Compound, it's an f/4.8. I use the lens without the disks, but with the conventional diaphragm in the compound shutter. It works wonderfully. I have no doubt the Imagon worked wonderfully well with the h/stop diaphragms. The two different wonderfuls are slightly (and only very slightly) different. It's all good!

You could spend a dozen lifetimes playing with the Imagon, and just be getting started... But that's like most lenses...

Using the aperture in the lens causes the loss of most of the Imagon effect as the aperture in the lens will mask off the effect of the outer part of the lens. If you want the "Imagon" effect then you must use the lens either with the disks, open or closed, or with no disk.

[Mark Sawyer]

Thanks for the informations.
Do you know if the lens cell can be easily transferred from the barrel version to a Compound No.5?
I can't try myself because i don't have a No.5, just No.4 and No.3.


I'd have to say "better try it first!" The Imagon 300mm came in versions that fit the Compound #4 and #5, and the Copal #3, so there are three sizes already...

Bob is right in that You lose the as-designed "Imagon effect" by using the conventional f/stops stops rather than the h/stops. But I've used it both ways and prefer the Compound's conventional diaphragm. The disks give a deeper depth of field and more "apparent" sharpness while maintaining a visible touch of softness. But you can vary the softness greatly by your choices with either the disks or the iris, from way-soft to way-sharp.

One danger of using the h/stops is that you may get the odd flares echoing specular highlights in the shape of the disk openings. Yes, it happens, and yes, it will ruin an otherwise lovely image.

I'm also a barbarian in that I sometimes use the Imagon wide open, which it wasn't designed for either. It's a lens with wonderful potential no matter how you use it.

[Bob Salomon]

The disks for the 200, 250 and 300mm Imagons are 54 mm in diameter where they push into the front cone of the lens.

[cowanw]

This thread has got me thinking what the difference would be in using the imagon with the Discs closed or using the shutter. The H=7.7 on the 300 mm lens has a opening of 31mm. If I close the shutter to this there should be no effect. If I take the disc off there should be no effect. A central 31mm fstop will be the same either way. It is after all a two element Achromatic meniscus at that point.
The imagon effect is really only using the outer holes open to some degree. Which is of course how you get the Kuhn bug Mark speaks of
Regards
Bill

[Bob Salomon]

This thread has got me thinking what the difference would be in using the imagon with the Discs closed or using the shutter. The H=7.7 on the 300 mm lens has a opening of 31mm. If I close the shutter to this there should be no effect. If I take the disc off there should be no effect. A central 31mm fstop will be the same either way. It is after all a two element Achromatic meniscus at that point.
The imagon effect is really only using the outer holes open to some degree. Which is of course how you get the Kuhn bug Mark speaks off
Regards
Bill

This was answered earlier in the thread. By closing the diaphram in the lens you block off the outside area of the Imagon changing the effect and loosing the Imagon's characteristic halation effects.

[Mark Sawyer]

I agree with Bob; there is a very specific effect from using the disks with the holes open, (and it's not the appearance of the "Kühn bug"!)

But Cowan is also right for those incidents where the outside holes are closed. The designers and engineers went to some considerable trouble to allow for those holes to be closed off, allowing the user to lose the "Imagon effect". I would guess they must have seen some value to having that option as well.

I also wonder whether much changes when one uses the disk (with holes closed) vs. the Compound shutter's aperture. The difference would be in the disk being a bit farther away from the lens than the shutter's iris. This should change the field curvature and coma, and perhaps pincushion/barrel distortion, although whether it would be enough to notice I'm not sure...

[cyberjunkie]

Nice. I have learnt a lot of things.
Only one question is left unanswered:
does anybody know if the optic of a barrel lens could be removed a directly fitted in shutter (Compound)?
Unfortunately many Rodenstock lenses were made with different cells, one version for barrel, and one for shutter. Apo Ronars are a good example.

I thank everybody for the help, this forum is the most valuable resource available on the web, for us LF lovers.
A last favour:
a few Imagon 300mm owners have posted on this thread, and maybe some others are reading; if you own the set of diffusion disks for the 300mm, and you have a flatbet scanner, please post a scan of the disks, with the crown of small holes in open position. I have inquired about the cost of the two disks i miss, but the cost is too high for a lens i payed 170 euros (including shipping). BTW, Bob Salomon wrote me that they can't ship abroad, so buying them new would be very complicate.
It would be a long lasting reference for all those missing some (or all) the disks, and a nice inspiration for all those who enjoy the DIY way, like i do.
I have seen other Imagons sold without disks in the past, and i am sure that somebody, like me, got the lens with one or two missing disks. Each original disk could be substituted by two hand made disks, one with just the central stop, and the other with the peripheric holes. It would be as easy (or difficult, as you prefer..) as making an hand made lens cap. Finding an old filter of suitable size would make it easier though. A filter frame with 52mm thread should have a rim diameter that just exceeds the needed measure. Just guessing... but i'm sure that if a nice soul provides the scans, most of us would find a way to build a set of working disks on a very small budget :D

Thanks

have fun


CJ

[Bob Salomon]

Nice. I have learnt a lot of things.
Only one question is left unanswered:
does anybody know if the optic of a barrel lens could be removed a directly fitted in shutter (Compound)?
Unfortunately many Rodenstock lenses were made with different cells, one version for barrel, and one for shutter. Apo Ronars are a good example.

I thank everybody for the help, this forum is the most valuable resource available on the web, for us LF lovers.
A last favour:
a few Imagon 300mm owners have posted on this thread, and maybe some others are reading; if you own the set of diffusion disks for the 300mm, and you have a flatbet scanner, please post a scan of the disks, with the crown of small holes in open position. I have inquired about the cost of the two disks i miss, but the cost is too high for a lens i payed 170 euros (including shipping). BTW, Bob Salomon wrote me that they can't ship abroad, so buying them new would be very complicate.
It would be a long lasting reference for all those missing some (or all) the disks, and a nice inspiration for all those who enjoy the DIY way, like i do.
I have seen other Imagons sold without disks in the past, and i am sure that somebody, like me, got the lens with one or two missing disks. Each original disk could be substituted by two hand made disks, one with just the central stop, and the other with the peripheric holes. It would be as easy (or difficult, as you prefer..) as making an hand made lens cap. Finding an old filter of suitable size would make it easier though. A filter frame with 52mm thread should have a rim diameter that just exceeds the needed measure. Just guessing... but i'm sure that if a nice soul provides the scans, most of us would find a way to build a set of working disks on a very small budget :D

Thanks

have fun


CJ
300mm Imagons mounted in a 3 shutter come with 2 disks, not 3.

The disks for those lenses are the 7.7 anf the 9.5. All modern Imagons (200 to 300) will fit a Copal 3 when the lens group in the back and the nose cone in front are removed from their NF mounrt.

[numnutz]

Why does no one ever mention the Imagon 360mm with H=5.8 - H7.7 and H=9.5 - H11.5 barrel mounted. I don't have the ND or yellow filter.

I have one and it seems to produce OK images when on my 10 x 8 Deardorff. In fact I will see if I can actually produce something worthwhile posting here in the next week or two.

nn :)

[cyberjunkie]

300mm Imagons mounted in a 3 shutter come with 2 disks, not 3.

The disks for those lenses are the 7.7 anf the 9.5. All modern Imagons (200 to 300) will fit a Copal 3 when the lens group in the back and the nose cone in front are removed from their NF mounrt.

Thanks for the precisation, but the original question (and my last post with the request for scans of diffusion disks) was about the older versions. Post war Imagons were fitted on Compound shutters, and had at least 3 disks, plus one or two filters; i have seen one in person, and many in photo.
I don't know if the barrel version had compatible threads.
My example (still on its way to Italy) probably is not so different from the post-WWII model, but has the "J" instead of the "I" in the name, and the focal expressed in cm.
It's not

a very early one, because it was made to work with diffusion disks.
I have posted a photo of the lens.

A scan of the disks and a quick meeasure of the optic cell would be a nice present for me, and a very nice reference for the future.

- For numnutz
I am green of envy :D
I'd be more than happy to own one of the long Imagons (sold only in barrel AFAIK).
The 360mm you have is the bare minimum to shoot 8x10, according to the opinions expressed by many users on this forum and elsewhere, i think i'll be happy with my 30cm. shooting at close distance. Your 360 would be more flexible, and better for portraits, but i was not given the choice :-(
I would be even happier to own a 420mm or 480mm example, but i have seen few of them on sale, and the asked prices are out of reach for me.


have fun


CJ

[Bob Salomon]

Thanks for the precisation, but the original question (and my last post with the request for scans of diffusion disks) was about the older versions. Post war Imagons were fitted on Compound shutters, and had at least 3 disks, plus one or two filters; i have seen one in person, and many in photo.
I don't know if the barrel version had compatible threads.
My example (still on its way to Italy) probably is not so different from the post-WWII model, but has the "J" instead of the "I" in the name, and the focal expressed in cm.
It's not a very early one, because it was made to work with diffusion disks.
I have posted a photo of the lens.

A scan of the disks and a quick meeasure of the optic cell would be a nice present for me, and a very nice reference for the future.

have fun
CJ
I have answered at least part of your question earlier and in several other Imagon threads. The opening in a Copal and Compur 3 was smaller and masked off part of the 300 so it could only use 2 disks. The Compound had a larger opening and the lens could reach full speed so it came with the 3 disks.

Unfortunatly, we only sell new items and do not have open diks that we can scan. You would have to find someone with used disks or someone who does not sell new ones to scan them. As the lens has been out of production for many years we do not have any that we can measure. But the 200, 250 and 300 all took the same diameter disks and had the same opening in their front cone.

We only distributed Rodenstock since 1986 so we do not have any reference images or material on older versions and how they may have differed. Our oldest catalogs for Rodenstock only go back to the 70s.

[cyberjunkie]

I found a set of photographs were an old Jmagon with focal in cm. is portrayed.
It is a 36cm. and not a 30cm. like mine, but i think that both of them were made the same way.
Well, it had SIX diffusion disks, and not two or three.
My request for a scan of the original disks is even more significant now, the additional disks could be very useful, because they can be used to control exposure (if the diaphragm is not to be used - something that would be impossible to do with the longer focals, that can't be mounted in shutter). Of course more disks would also mean a better control over halation.

have fun

CJ

[cyberjunkie]

Ehmm... i forgot to evidence that the previous photos showed an Jmagon example with ONE-position disks.
My lens has TWO-position disks, as the engravings on the disks clearly show. There are two different "H" values for each disk. I still don't have the lens in my hands, but i don't see how the picture could be interpreted in a different way.
Here is another image of a 36cm. Jmagon that should be of the same vintage (it looks exactly as mine).
In this case the disks are only THREE.

The two variants can be easily recognized because the first one has two large indents on the front, and the second (see the image below) has the engraving:
„Jmagon"
The first character is a low quotation mark.


have fun

CJ


P.S.
Bob, i thank you very much for your contributions,on this thread and elsewhere.
When i was asking for a scan of the old diffusion disks i was NOT making a request to you. Sorry if you felt that way.
I was just asking IF somebody has got the old disks, and could make the scans.

[cowanw]

From what I have been able to glean, the sets with 3 rows of holes are theoriginal design circa 1931. The circles were changed to two in 1935. I don't know when the yellow filter changed to green then grey, but I think the purpose of he filter changed from a minus blue (having to do with ortho paper or to do with chemical focus) to a green then grey filter (having to do with halfing exposure). So CJ's first set would be 1931-35 and the second set 1935-45.

5.8-7.7
central hole= 31.32mm
middle holes= 5.52mm centred 22.3mm from centre
outer holes= 4.13mm centred 28.13mm from centre
7.7-9.5
central hole= 25.89mm
middle holes= 4.53mm centred 19.25mm from centre
outer holes= 3.44mm centred 23.425mm from centre
9.5-11.5
central hole= 21.48mm
middle holes= 3.67mm 15.71centred mm from centre
outer holes= 2.6mm centred 19.34mm from centre
Regards
Bill

[cyberjunkie]

So CJ's first set would be 1931-35 and the second set 1935-45.



Thanks a lot!!
It's not a scan, but i guess that with help of some pictures, and with your carefully made measures, i should be able to redo the two missing disks.:p

Thanks again for this final clarification about pre-war Jmagons.
From what you write, i get that the first set of pictures (i posted) refer to the 1931-35 model (with six "fixed" disks, with a crown of three concentric holes).
The second post refers to the same model i have purchased (i.e. the 1935-45 version, with three "modern" disks, and with the name Jmagon engraved between quotation marks).

I think that your post will serve well as a future reference for all those seeking informations about pre-war Jmagons.

cheers

CJ


P.S.
Your post brings forward one (unanswered) question:
why did they change the filter type over time?
Was it because the changes in available emulsions?
Or because of a change in the lens plan?
The latter option implies the need to overcome a degree of chromatic aberration, with older Jmagon sets... or maybe just the simple truth that mostly everybody used B&W at the time?
AFAIK a fully achromatized doublet should put blue light in the same plane of focus, with a SMALL error towards the violet end.
It would be very interesting if somebody could further elaborate about "yellow vs green vs 2x" filter issue.

[cowanw]

If you have not read this, you should
THE SOFT-FOCUS LENS AND ANGLO-AMERICAN
PICTORIALISM
William Russell Young, III

Google it and then download or print 359 pages.
Much of the thesis has a theme of the syntax of the time. There is also a good discussion of focusiong and exposure.
With regards to this topic I expect people (particularily in Europe) in 1930 were using ortho slow films or plates. Hence, yellow filter with as little loss of speed as possible. Later with faster panchromatic films there may have been a need to use a 2x filter to make the large apertures useful.
The change to fewer and closer to the centre holes would certainly result in less of the Imagon effect. At the same time Pinkham and Smith lenses were getting more moderate in their effect as well.
Regards
Bill

[cyberjunkie]

If you have not read this, you should
THE SOFT-FOCUS LENS AND ANGLO-AMERICAN
PICTORIALISM
William Russell Young, III



Thanks cowanw
I already downloaded that nice thesis, and read a few pages here and there :)
I think i have to print it on paper, a treaty like that one can't be read on a computer screen with full satisfaction

have fun

CJ

[Bob Salomon]

"why did they change the filter type over time?
Was it because the changes in available emulsions?
Or because of a change in the lens plan?"

Color film. Yellow filters do not result in very pleasent color prints. ND filters don't effect the color. The filter is used to maintain a desired H stop in stronger lighting conditions.

[cowanw]

Colour film does not really explain the use of the green filter that was used for a time between the the yellow and the ND. That was when the change to 2X filter factor occurred.
Green is an odd choice from todays perspective; obviously not for colour, and as a Black and White filter not usually used for women as it gives a swarthy look.
Regards
Bill

[Bob Salomon]

It was also for B&W. And film emulsions and types and sensitivities have changed quite a bit over the long life of the Imagon.
The filters used on the Imagon were made by Heliopan and Heliopan also made filters in the Imagon push-on mount as accessories. So it may be possible to find other filters as well.

[russyoung]

Nice to see that the old dissertation actually is read by someone... the university has a counter by will not reveal the results to the authors so I have no idea whether it gets viewed/read or not... sorry about the missing illustrations, they are some of the most crucial in the book - you need to understand bokeh to evaluate soft focus lenses; it distinguishes images formed by a soft focus lens from those created by any other method such as a degrading filter (such as a Duto) or net, darkroom or PhotoSnot.

Yes, early Imagons and the Kuhn Anachromat had fixed discs that did not open and close. Longer focal length pre-war lenses had SIX discs; have conflicting information about the 200mm and less focal lengths.

The Imagon glass has changed over the years, too. I own several and I have been loaned several to test. At a given T setting, the pre-war models have a different look, which I prefer. They are very tricky to use wide-open, the later versions less so.

A very careful reading of Kuhn's original instruction is useful. Later instructions are written by Joseph Foldes (I'm trusting memory here and that may not be exact). Kuhn's instructions are far more detailed and way more useful.

Kuhn advocated a yellow-green filter in the 1930s as the single most useful filter. Try it on a Tyrolean landscape and you'll see what I mean... LOL It really is wonderful on trees and grass or even sea and clouds, not heavy handed, very subtle. Kuhn did NOT especially envision it as a portrait lens...

Russ
aka William Russell Young, III, Ph.D.

[cyberjunkie]

Nice to see that the old dissertation actually is read by someone...


Thanks for your nice work, Russ!
I think you'd be surprised by the huge number of downloads :D
As already stated, i didn't read it at length, i think it's much better to print it on paper and read it the old fashion, but it was enough to understand that it would be a very nice basis for a book on the subject. Who knows... if the " soft focus" craze, that caught up in Japan and Korea, will spread in China, and maybe India and arab countries, there could be enough interest to justify the publishing of a nice book on the subject.
I would happily buy a copy! :D

Back to the Imagon/Jmagon.
Do you have any clue about:
1) when the changes in optical design were implemented?
2) why and when there was a switch from yellow to green filter?
3) at the end of Kuhn's instruction leaflet available at Cameraeccentric, there is a nice table, where is clearly stated that the biggest Imagon available in Compound shutter was the 300mm, longer focals were supplied only in "Special shutter". I guess that it must be something like a Packard/Silens/Zettor shutter made in a special attachment for the Imagon... but that's just my guess. Did you find out what did it mean?
4) do you know what's the year of publication of that leaflet? It would be interesting, as the photo portraits yet another version of the lens! It still has the "J" in the name, but i see no quotation marks, the disks look the same as mine, tough.
5) last one, or we get too far... what's the relation between Imagon/Jmagon and Imagonal? BTW, i have seen the latter only as casket (i.e. ImagonalSatz)

No prize, sorry :( but the quiz is open to everybody

have fun


CJ

[Bob Salomon]

There was a book published in West Germany on the Imagon. It was only printed in German, however. It was available at least up to the late 80s. Someone "borrowed" my copy and it was never returned, along with an English transcript of it.

[russyoung]

Dr. Alfons Scholz: Das Imagon Buch (Munich: Rodenstock, 1979)

Is the book Bob mentioned. Despite its size, there are many questions left unanswered, perhaps forever, due to the destruction of records during the war. Also, the author was clearly not artistically inclined so his approach to application is rather lacking. I cite it several times in my diss.

Russ

[keith schreiber]

Hi Russ,

Nice to run into you here. I just earlier today mentioned your name in conjunction with something I posted on the tree thread. Hope life is good down on the farm. Do you ever miss NM? It's just not the same without ya!

Cheers,
Keith

[keith schreiber]

Sorry folks. My previous post should have been a PM. :o