Originally posted by Imageman ...................
I had assumed that doublets would have continued to be a significant part of early photographic lens choices, and searched for information about the use of these designs, but found nothing. So im very interested in your comments that doublet lenses were used to create soft focus images.
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I have found that the triplets produced in large numbers a few of which I am privileged to own do deliver beautiful soft focus images with typical soft focus "glow".
Have a look at the Steinhill Munchen 50, the Shacht Travenar 50, and the Meyer Domiplan.
As im sure your must be aware cooke triplets must have a correctly aligned rear element or the lens is a dog and the traditional cooke triplet carries external adjustment screws for this very purpose, the domiplan and steinheil often show this characteristic of misaligned rear element. That's why the domiplan is usually condemned as very poor lens. Im convinced that in almost every case the domiplan simply need re calibrating, or the photographer is expecting a razor sharp image but is looking at a soft focus image and is unaware of it.
I know the steinheil carries the external adjustment screws to adjust and calibrate the rear element, the Schacht does not. I haven't had the opportunity to examine the domiplan.
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I agree with you, triplets very often have a very nice "signature", especially wide-open (or stopped down very little).
I also agree with the notion that old triplets can be affected (very badly!) by improper remounting (after cleaning) or other "incidents" which altered the specs of the lens.
The Cooke triplet is probably the most "sensible" optical project. A slight alteration which makes almost no difference in a Tessar (or in a old, simple tele design), would introduce plenty of aberrations in a Cooke design!
Usually it's not "misalignment", if the lens wasn't banged against a hard rock, or wasn't reassembled by a madman, that's seldom the problem.
More often it's a matter of "spacing" (i.e. distance between the optical elements). Some lenses had a LONG life, and where dismantled more than once... forgetting a spacer ring, or not screwing home a retention ring (for example because the thread is oxidized) is more than enough to dramatically change the behavior of a lens.
One caveat thought:
a conventional triplet optimized for sharp rendition (that is, 99% of the triplet production) is NOT a soft focus lens!
Changing the spacing of the elements, unscrewing either the front or the back glass, COULD change the character of the lens, under-correcting the spherical aberration, but it's not the only thing that's changed!
Focal length is changed for sure, and possibly other aberration are introduced.
The super famous Cooke Portrait lenses were made with an adjustment device on the barrel, which allowed to change the character of the lens from sharp to soft, and the other gradations in-between.
Most photographer, even those who are very informed about lenses used in digital and 35mm photography, don't know that much about "true" soft-focus lenses, cause the vast majority of them were made for large format (or even ultra large format).
Even for medium format there were VERY few available lenses, cause the 99% of vintage soft-focus lenses were made with no focusing barrel!!
The shorter focals often had a conventional leaf shutter, while the longer focals had a simple barrel, and were used with an accessory pneumatic shutter, or a lens cap/hat.
For medium format i have seen Imagons mounted on the Zork focusing barrel, or old soft-focus lenses in barrel adjusted on a medium format bodies with focusing bellows and focal-plane shutter (like old Zenza Bronica or Rollei cameras, IIRC).
Conventional triplets made for 35mm cameras are not truly soft focus, most of the times they just have a slightly under-corrected spherical aberration, hence the hint of halation with the diaphragm wide-open, and the beautiful "triplet bokeh".
Unfortunately a 50mm is too short a focal to have a really thin DOF.
Standard 300mm triplets (which were the "normal" lens for 8x10 inches sheet film) have a wonderful separation of planes. Wide open, the ear is out of focus, if you focus on the pupil.
Depth of focus have an inverse relation with the absolute focal length, not the relative one. That means a simple thing: a 300mm on digital has the same DOF of a 300m on 8x10". It's not dependent on the size of the film/sensor, even if the same focal is a normal lens for the bigger format, and a very long tele for the smaller one.
So i have a simple advice. If you want to exploit the "soft side" of a generic triplet lens, better look for a somewhat longer focal.
You mentioned Steinheil...well, there is the wonderful Trioplan.
They are already not exactly super-cheap, but those made for the smaller format are definitely affordable.
There are examples with focusing barrel, with the "V" or "VL" engraving (which means coated), which should be well worth experimenting with.
Other Trioplans can be expensive (like the longer focals for large format) or VERY expensive (like the 260mm soft-focus, with the "soft ring" which adjust the spacing of the laments).
If some pentaxian has the will, and the determination, to experiment with "true" soft lens, all that's needed is a bellows, and a friend who owns a lathe (and knows how to cut threads and make adapter rings).
With some luck, a combination of chinese step-down/step-up rings, and a M42-to-PK adapter, could be enough.
Not many soft-focus objectives are available in a FL short enough to be usable in APS-C format, but with some patience there are some.
I have just seen on Ebay a 200mm Imagon mounted on a Novoflex LEINO tube. To use it with a Pentax digital body, you'd need just a M42 bellows (to focus the lens), and a LTM-to-M42 ring (to mount the LEINO on the M42 thread of the bellows).
There are shorter Imagons, but they are not so common, and there is the Fujinon SF 180mm, which was made in shutter and in barrel, IIRC.
Both optics use those weird "tea strainer" rings (the Imagon in front of the lens, the Fujinon behind the front glass), which are used to control the amount of light rays coming from the periphery of the front glass.
The rays passing through the lens axis are super-sharp, the rays coming from the borders are very affected by spherical aberration (soft). The use of different "tea strainers" irises allows to control the amount of halation superimposed on the sharp layer of the image.
I am not a post-production expert (i am a network administrator and an hardware expert, not a graphic!), but i am quite sure about it: there is NO filter which gets close to that rendition.
I'm not even sure that the best software solutions can equal a simple Zeiss Softar filter!
Probably with a more structured software-only approach, using different tools and with a very good knowledge of the intricacies of Photoshop, a very good result could be achieved.
I've seen incredible things made with bitmap graphic software (Photoshop or similar programs), but i've also seen with my own eyes the amount of time and of graphic wizardry needed to achieve those results...
The use of a single plugin, not matter how good, can't get you remotely close to that kind of quality. It's not just mixing a sharp layer with an halation layer, you got to reproduce the smooth shift between out-of-focus and in-focus planes, and reduce the DOF to almost nothing.
The advocates of the software-only solution should take a look at the pictures made by the neo-pictorialists, and to the portraits of Hollywood stars and starlets made during the twenties.
Most of the times the proper soft-focus lenses were used with some restrain, stopping down a little to reduce the amount of softness and allowing to easily "read" the facial features of the actress, but at the same time keeping the right amount of "glow".
For those interested in a low-cost approach, there are a few good choices.
One example: adapt to your bellows the simple meniscus used in the very common Kodak Vest Pocket (which is still very cheap on Ebay), paying attention to uncork the lens (i.e. removing the front stop).
An even cheaper solution: use a diopter lens (better if it's an achromatic doublet made of two cemented elements); if you can find a filter with +8 engraved on its mount, it's a 125mm lens.
Of course there are other medium format soft-focus lenses, produced by other makers, which can be easily used with the right adapter (if it's one of those made by the chinese, and easily available on Ebay, the expense should be very low).
I'm back at home now, and i have the 120mm at hand. Unfortunately i don't have the adapter for P67 lenses here, so it will take some time to have it tested on digital bodies.
I hope i'll get the 85mm f/2.2 in a week or so. I will test it as soon as possible, cause i'm very curious about its performance with digital sensors.
It's a kind of lens which should work well with digital, the only concern that came to my mind is the possible presence of a lighter "spot" at the center of the image. Some lenses of similar FL, originally made for analog cameras, show that kind of problem, due to inter-reflections between the sensor surface and the rear glass. SMC lenses shouldn't be prone to that kind of problem, though.
Wow, i've made a loong post... time to stop
I hope at least i've given a couple of worthy suggestions.
ciao
P
Last edited by cyberjunkie; 06-06-2014 at 08:46 PM.