please help me with my imagon

[eddie]

hi all,
i am playing with my "new to me" imagon 300. i would appreciate any advice on shooting with it.
i have just processed my first few negs and they are drying now. i am looking for advice on what f stops to use. can i use my disks (i have 3) and stop the lens down? how far can i stop it down before i negate the diffusion effect?
which disks work best in what kind of situations?
so far i have shot it wide open with the 5.8 disk and i have used no disk at f16. interesting results. i am just trying to keep from spending all my film testing this lens. any quick tips you can give (photos with descriptions is great!) me would be great.

thanks

eddie

[Ted Harris]

Eddie,

You should use the disks with the normal aperture ring left wide open. The wider pen the disk the greater the off center diffusion. If you search the archives here you will find several posts on using the lens. In short, you need to focus t the taking aperture. BTW, if you are using the 300 with 5x7 that is the format for which it is designed, not 4x5. Not t say it won't work with 4x5 but the 250 is optimized for 4x5.

[eddie]

thanks ted,
i was just looking to save myself some time on the learning curve.
i am using the 300 on an 8x10. i shot several wide open. it seems to cover the whole 8x10 sheet.

thanks

eddie

[Mark Sawyer]

Hi, Eddie~

I use a 300mm f/5.8 Imagon on an 8x10 occassionally. The h/stop disks are one option, the other option is using the standard diaphragm as f/stops. Yet another is using it wide open. The 300mm Imagons were factory recommended for 5x7, but if you were into factory recommendations, you'd never use an Imagon to begin with.

The Imagon changes quite a bit with every f/stop down to about f/16 or F/22, and even there, after losing the abberations, it's still somehow a bit different than a "normal" 300mm.

All I can say is, "play with it..."

[Thomas Greutmann]

Eddie,
the Imagon has become one of my favorite lenses, not so much for the softness but for the ability to produce images which show truely radiating light. I use it mostly for outdoor/landscape. I think this image illustrates this very well:



As to your questions on how to use the Imagon: You should use it with the aperture fully open and adjust aperture with the H-stop disks. The h-stop value corresponds to the f-stops, so H=7,7 is close to f8. Each disk has two H-values, the lower value should be applied when the disk is used with the little holes fully open, the higher value (smaller aperture) when the disk is closed. Generally, a smaller aperture will create sharper images, so for instance H 7,7 (largest aperture disk closed) is softer than H 11,5 (smallest disk closed). But softness changes depending on the light if you open or close the disks. You have to experiment, with LF you can check the difference on the groundglass.

A few hints based on my experience. You will get the unique radiation effect of the Imagon only if there is a strong light/dark contrast (a difference of several f-stops between light and shade). The effect disappears for subjects with flat contrast, outdoors you will have the effect only in bright sunlight and against the sunlight. I look for these situation. You can see this in the image below: strong contrast and radiation in the background trees, but flatter contrast and no radiation in the water in the foreground. I mostly shoot against the sunlight with the Imagon.



If you use the disks fully open and you shoot subjects with spotlights you will notice a strange pattern from the disks, see full size cropped image below:



It is called the "Kühn bug", in honor of the lead engineer who developed the Imagon in the thirties. You hardly notice these bugs on the groundglass, so I have made a practice to shoot one negative with the disks open and one with disks closed, just in case I get these unwanted bugs.

As you can see I shoot B&W, but there are also applications in color photography, so I have read. In particular, the Imagon will help to reduce contrast in bright daylight, so the Imagon (supposingly) will help in situations with strong contrasts between shade and sunlight, such as landscapes/outdoor sceneries in summer. You should be able to use the standard aperture without the disks in these situations, as softness is not the primary goal.

Hope this helps. Go and play with it. Look for subjects with strong contrast. And don't give up after a few disappointing results. I had my share of these before I started to love this lens.

Greetings, Thomas

[Peter K]

It is called the "Kühn bug", in honor of the lead engineer who developed the Imagon in the thirties. You hardly notice these bugs on the groundglass, so I have made a practice to shoot one negative with the disks open and one with disks closed, just in case I get these unwanted bugs.

Sorry Thomas,
Heinrich Kühn was an in Austria born photographer, who asked the lensmaker Dr. Staeble from Munich for a soft-focus lens. After the bankrupt of Dr. Staeble's factory, Rodenstock took over the fabrication of the Imagon.

The "Thambar" soft-focus-lens for the Leica used also such kind of diaphragm to mix the spherical undercorrected outer parts of the lens with the sharp center part.

Peter K

[russyoung]

You need to read the Imagon instruction booklet posted by Seth on his website:
www.cameraeccentric.com

The modern 300mm will not open as widely as the period models and hence the amount of diffusion is less.

Sorry Peter K but the THAMBAR had an opaque spot on a screw-on filter. This doesn't relate to the brilliant idea of Staeble which mixes the proportions of axial and central light rays.

Russ

[Ted Harris]

Russ, no time to look this am, but IIRC, Bob Salomn has pointed out i the past that one of the postings there includes some totally incorrect info on focusing.

[russyoung]

Good morning Ted-

Hmmm. As an historian, one measure of accuracy is 'how close is the informant to the source?" The two sets of instructions posted at Seth's site represent the factory engineers' thoughts at that time- which needs to be stressed because even those instructions are at slight variance with each other. As both film and tastes changed, the instructions changed.

Having used IMAGONS (120mm, 200mm, 250mm, 300mm and 420mm) for several decades, they are very idiosyncratic lenses and use varies with the contrast (as Thomas points out above), and ones own operating technique with their view camera.

In summary, the factory instructions were almost undoubtedly correct for the film and preferences of their era. Now the question becomes would you prefer to work from the instructions of Dr. Heinrich Kuhn, the inventor, as posted at Cameraeccentric, who clearly knew how to wield this lens with aplomb, or by following the instructions of someone far removed in time and space. It would be interesting to place Kuhn's exquisite images next to those prints made by someone else giving instructions at variance with his...

Your choice and your mileage may vary.

Russ

[Ted Harris]

Hi Russ, as you know I am also a long time user and I agree completely with your comments, especially as to their idiosyncratic behavior. My recollection is that Bob was referring to some of the focusing instructions in the typewritten document on Seth's site, not the factory brochure. Hopefully he will chime in here.

I'll go so far as to underscore the importance of contrast. When working in the studio you get the best results by using the highest possible contrast lighting, completely different from the portrait lighting you would use with other lenses. It remains my favorite portrait lens in either the 250 or 300 variety.