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Ernest Purdum
2-Dec-2003, 12:39
A new article,
Soft-Focus Lenses and Techniques (http://www.largeformatphotography.info/soft-focus.html) by Ernest Purdum has been posted on largeformatphotography.info. [Note: this was posted by QTL using EP's address
so that EP would be emailed any comments.]

Bob Salomon
2-Dec-2003, 13:34
The Imagon has been available in 5 focal lengths over the past decade; 120mm, 150mm, 200mm, 250mm and 300mm. While all are now out of production there are still some new 250mm left in our stock.

The 120 and 150mm were primarily sold in a shutter and a helical focus mount that could be used on 35mm SLR cameras (with a T2 adapter) or on focal plane shutter MF cameras as well as Hasselblad 500 and Rollei 6000 systems (Rollei even supplies and adapter ring for them with their focusing shutter tube accessory). The shutter/focus mount system was made by Schmachteneurg

The 200mm was corrected for 6x6 to 6x9cm cameras and an adapter with camera mount and focusing helicoid was available for it from Rodenstock and from Zork. Both also offered a conversion mount for Mamiya RB and RZ cameras.

The 200 to 300 were available in either Copal 3 or NF mounts.

The Imagon and the Fuji are different in the way they use the discs. The Imagon uses discs that are placed in front of the front element. Depending on the lens there are 3 discs (the 300 has 2 on later production). The effects are quite different with the Imagon in that the lens is a 5.8 (200 to 300mm) without a disc or 5.8 with the first disc fully open. But the degree of halation is different. Same with the first disc fully closed and the 2nd disc fully open. Both are 7.7 but the halation is different. Again with the 2nd disc fully closed and the 3rd disc fully open. The exposure is the same and the effect is different.

So with the Imagon you can maitain an exposure and change the halation simply by the choice and setting of the disc or the use of no disc. In addition the Imagon is shipped with an ND filter which can let you have additional changes in halation while maintaining a desired aperture.

So yes, both Rodenstock and Fuji have disks - but they are used and work differently.

Bob Salomon
2-Dec-2003, 13:36
" The Zeiss Softar seems to be the most highly regarded device of this type. It has a series of concentric thread-like rings formed into the glass and is rather expensive.. "

No that is the Duto type diffusion filter.

The Zeiss Softar has random small lenses molded into the acrylic material. These look somewhat like raindrops on the Softar and you can feel them as you run your finger over the surface.

Arne Croell
2-Dec-2003, 13:45
An older version of the 300mm Imagon was also sold in a Compound 5 shutter, not only NF mount.

Bob Salomon
2-Dec-2003, 14:42
Arne,

The older one came with 3 discs since it was in a large enough shutter to use the 5.8-7.7 disc. The 3 shutter has too small an opening so that disc can not be used. There were also longer Imagons in the larger shutter sizes.

But those days and those shutters are long gone and the parts for those shutters are not readily avaiable any longer so there useful lifetimes are diminishing.

dangal
2-Dec-2003, 15:28
"A still earlier Wollensak product was the Verito. Except for the two smallest sizes, this was an f4 lens, the back group of which could be used by itself." Which I have been doing with great success. I have been taking close-up photographs of nautilus and pyramid shells with a verito 7 1/4 F4 lens mounted on a copal # 3 shutter with the rear section only which double-up the focal lenght. I Have read this possible idea in this forum before and I was reluctant initially but after giving it a go with the shells I have become in love with the results that I have been getting at F8. Larger apertures produces "too soft" an image to my liking. The two best image that I have produced I will enlarge it to mural size this weekend(4 x 5 feet) using rodenstock 150 rodagon-G two stops down. (Thanks Bob S. I have been getting great results with this recomendation and great lens). Mural size soft focus image is great!

Jonathan Brewer
2-Dec-2003, 21:44
A very informative article, I've had some good results with black toule netting, you can find this stuff at a flower shop(they use an amount as frills around flowers), I double it up on subject matter 10' or so and farther, I triple it up on close-ups/tight heads, the logic being that I found that distance is a function of whatever diffusion you're using, so much at a certain distance is too much with that same amount, but just right/submerging its presence as it merges into you texture/lighting at a closer distance from the lens.

Black toule netting looks like womens stocking but when used sparingly appears as a much more subtle 'smoothing' that merges into tone and light.

Steve Hamley
2-Dec-2003, 22:22
Folks,

An interesting post and article - thanks to Ernest.

Here's a link to a 1998 Usenet post in which the late Steve Grimes posted a couple of messages about soft focus lenses. I've experimented some with "non camera" lenses, as has Mark Tucker if you search the old photo.net archives. He used a magnifying lens from a toy store, and I used a single meniscus close up lens taped to a shutter as recommended in the Usenet post. The close up lens actually produced a very nice result.

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&threadm=01bd38a9%24f734c0e0%24654106d1%40default&rnum=4&prev=/groups%3Fq%3Dportrait%2Blens%2Bgroup:rec.photo.equipment.large-format%26hl%3Den%26lr%3D%26ie%3DUTF-8%26selm%3D01bd38a9%2524f734c0e0%2524654106d1%2540default%26rnum%3D4

There was also an article in View camera magazine not too long ago about making lenses using combinations of close up lenses.

My latest project is to remount a 360mm Universal Heliar into a Compound 5 shutter. I've been told it will lose about 1/2 stop, but this seems acceptable for gaining shutter speeds since the halation is controlled by the diffusion ring and not by the aperture. Any comments or suggestions?

BTW, I picked up an older 300mm Imagon with 2 missing discs (it has the H9.5 - H-11.5 disc) to get the synched Compound #5 shutter, and at the price I paid, I figured the glass was junk or the shutter would need major repair. Surprise! The shutter, disc, and the glass are in superb shape. So Bob, got discs?

Thanks!

Steve

Bob Salomon
3-Dec-2003, 02:39
:So Bob, got discs?"

Yup

Jim Rice
3-Dec-2003, 20:43
The VC article to which Steve refers is in the July/August 2002 issue.

Bob Salomon
4-Dec-2003, 07:22
"So Bob, got discs?""

Now that I am back in the office I checked and for the 300mm there are 4 disks and 2 ND filters left in stock. 3 of the disks are 7.7 to 9.5 and only 1 is 9.5 to 11. So if that is the one you need act fast.

steve simmons
6-Dec-2003, 03:00
A few years ago View Camera did an article on soft focus lenses and gave a reference to a self published book on the topic. I am guessing it was in 97 or 98.

steve simmons

Arne Croell
17-Feb-2004, 08:18
To add one more to the list, I just learned that another lens was the soft focus version of the f/3-3.8 "Porträt-Trioplan" from Hugo Meyer Görlitz. The Trioplan is a basic triplet. The soft focus version was similar to the Universal Heliar from Voigtländer in that a separate control moves the negative center element of the lens. That version was available in 260, 300, 360, and 420mm focal length (The regular Porträt-Trioplan ranged from 75 to 480mm).

Rory_3532
17-Feb-2004, 09:15
Is there anything that these lenses can do that can't be done more easily, more predictably and more cheaply in Photoshop?

David A. Goldfarb
17-Feb-2004, 09:18
Absolutely. They can produce a natural effect. Photoshop blur always ends up looking unconvincing to my eye.

Paul Fitzgerald
9-Sep-2004, 21:42
Hi there, I hope this is the right place for this. I was playing around and found a new 'soft-focus' lens the "JML OPTICAL 209 f/8" process lens, also badged "F GOODKIN ASTRO" 8 1/4" f/8 PROCESS LENS JML". This is an ultra flat field, fully corrected process lens at f/8 and smaller, but is a curved field soft-focus lens at f/4 - f/6.3 very much like 'VITAX' and still color corrected. This modification does require machine work to the barrel the allow the selector to turn fully open but is well worth the effort. Two warnings,(1) most of these have the lens cell glued in place and must be treated with acetone to loosen them; (2) the aperture ring assemblies are ultra-precise and adjustable, ALL PART MUST BE MARKED BEFORE BEING REMOVED to re-align them. This works well enough that I have 2 to play with. Just a thought.

fergs1
8-Jul-2005, 18:41
greetings, I have a 7 1/4 in Verito lens in a crappy studio shutter. Does anyone know if this lens is chromaatically corrected, as I haven't used it yet and setting it up will take time so before I do i'd like to know what i'm dealing with.

Ernest Purdum
8-Jul-2005, 19:37
Chris, yes, Verito lenses have chromatic correction.

robert_4927
8-Jul-2005, 20:00
By removing the front element on a 14.5 inch verito I realize that it makes it a 24" lens but what happens to the aperture setting? does f4 become f5.6 or f8 ....ect...ect?

Ted Harris
9-Jul-2005, 07:36
Seeing some recent posts here I thought I'd throw in a plea. I am in the midst of an article for "View Camera" comparing the performance of the 'modern' soft/variable focus lenses ..... the Fuji SF250, Rodenstock Imagon 250 (one of the last ones manufactured in a modern all black Copal shutter) and Cooke Portrait PS945 229. I would love to include the original Pinkham & Smith on which the Cooke is designed but have not found one yet to test. I may have a line on one but all help is appreciated! I am debating including the Congo and perhaps one or two more 'classic' lenses. I do have a 9" Verito that Michael Mutmansky lent me to use and we shall see.

Too many lenses and too little time and space unfortunately and I do want to keep the focus on the modern offerings as they will remain easier to find as time passes! My focus (excuse the word play) is primarily on the differences in performance of the various lenses and the sort of images they make Technical details of the optical design is important too as there are significant differences in how the lenses perform and how you use them. A number of interesting possibilities that go way beyond portraits. My goal is to have this done for the September issue.

Looking forward to any info or leads.

Thanks in advance.

Ernest Purdum
9-Jul-2005, 07:52
Robert, the f number of a lens with only one cell can be found just by dividing the focal length by the diameter of the opening. (This doesn't work with combined lenses because it is not the actual aperture but the apparent aperture that counts..You have to measure what the diameter of the aperture appears to be from the front.)

I don't have a Verito to measure. Wollensak gives the lens diameter of the 14 1/2" size as 3 1/2". If the diaphragm opens that far, this would give an f number of 6.8 as the top aperture.

robert_4927
9-Jul-2005, 20:23
Ernest, that makes sense. But let me understand this.... with just the rear cell the normal f settings would be as follows? ....on the old studio shutter f4 becomes f6.8......f5.6 becomes f10.2......f8 - f13.6......f11- f20.4.....f16 - f27.2......f22 - f40.8.....Am I figuring this right?

David A. Goldfarb
10-Jul-2005, 10:12
Ernest (and others who know their optics better than I do offhand)--does that rule apply if the stop is way out in front of the element? On my 14.5" Verito, the stop is 3" in front of the rear element. I've never tried using the single element, because I don't have a camera with enough bellows (but I have a new 36" bellows on order for my 11x14" camera, so maybe in a couple of weeks...).

Ernest Purdum
10-Jul-2005, 21:40
Robert,

I knew I should have been paying more attention in math class. The series of f stops on your lens barrel is based on the square root of two, which is roughly 1.414. Now whatever starting point you measure, 1.414 X that figure will be the next stop down. Two times the starting figure will be two stops down, and so on. f6.8 may not be the right starting point, since the opening may be less than the full diameter of the lens, but if we open the diaphragm to a reading one stop down from wide open, (f5.6 in your case) the actual f number should be 1.414 times the wide open figure. The next marking (f8) will be twice the starting point, and so on.

David,

The distance from the lens to the stop won't make any difference in the f number. The stop placement is chosen to avoid coma and field curvature.