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Soft-Focus Lenses and Techniques

massivan

19/03/2019 13:49:02

By Ernest Purdum © 2003 for largeformatphotography.info

Critic A: "This image has a certain ethereal quality.

Critic B: "It's a fuzzy picture."

The use of soft-focus lenses has always been somewhat controversial as well
as rather difficult. To me, they are a rather specialized tool, something
like the fish-eye lenses. I have seen many fish-eye pictures I didn't care
for at all, but a few I found wonderful. Similarly, there are awful
soft-focus images, but some of the all-time great photographs are soft. The
names Stieglitz and Steichen jump into mind. Many think of these lenses as
merely a way to "erase wrinkles", but in the right hands they can help in
creating beautiful landscapes and provide a mood that strengthens other
photographs. Soft-focus lenses are tools. Like other tools they can
provide results that are good or bad.

No lens is perfect. All lenses have defects, known as aberrations, that
cause the image to be less than perfect. Softness of focus is the result of
one or more of these aberrations being strong enough to be noticeable. One
aberration is the "spherical". It is comparatively easy to grind a lens
surface which is a segment of a sphere, but a surface like that can't quite
put an image into correct focus. Lens designers have to use several
surfaces working together to reduce spherical aberration to useful levels.
The most common means of producing a soft-focus lens is to allow some
spherical aberration to remain. A caution. Some very early soft focus
lenses also had significant amounts of chromatic aberration, they couldn't
focus different colors onto the same surface. Unless you intend to use only
blue-sensitive film, no longer readily available, these would not be a good
idea. The tip for identifying these lenses is that they will not contain an
achromatic component - two or more glasses together. Two examples are
the Dallmeyer-Bergheim a telephoto soft-focus lens, and the Puligny-Puyo.

Many photographers still alive, and perhaps still working, today, started
off with a soft-focus lens, although they probably have never thought of it
that way. During the 1920's and 30's, Box Brownies and other simple cameras
were apt to be fitted with a single meniscus lens - one piece of glass with
convex curves on both surfaces, thicker in the middle than the edges. These
exhibited most every aberration in the book, but had a small enough aperture
that images were usable.

There are two categories of people. Those who divide into categories, and
those who do not. There are two categories of soft-focus lens. Those which
provide selection of softness without changing the aperture, and those which
do not. let's discuss the latter first. The smaller the aperture, the less
spherical aberration affects the image. This provides the basis for making
the simpler forms of soft-focus lenses. You need only two pieces of glass
to make a basic achromat, a lens which will focus different colors of light
together well enough to provide a usable image, but which has too much
spherical aberration to produce a sharp image at larger apertures. Put a
diaphragm in front of this lens, stop it down to f16, and you can make a
fairly sharp photograph. This is the construction of two of the four
soft-focus lenses that I am aware of being made today. These are the
Rodenstock Imagon and the current version of the Fujinon soft-focus lenses.
(Earlier Fujinon SF lenses were triplets.) These lenses have peculiar
diaphragms - removable discs with central holes surrounded by a ring of
smaller holes which can be opened or closed. Buyers of used lenses should
be sure that all the discs are present. Imagon lenses are made in 250 and
300mm focal lengths as well as versions for medium format cameras. The
Fujinons come in 180 and 250mm lengths. There can be an occasional problem
with these lenses. Strong highlights can be surrounded by a ring of little
lights - an image of the diaphragm.

The other two current soft-focus lenses are made by Yamasaki and Cooke.
Under the "Congo" name, soft focus triplets are made by Yamasaki in 150 and
200mm lengths. To date, Cooke produces only one size, the 9" (229mm) PS945.
The Cooke design is based on a very old lens, the Pinkham-Smith, which,
along with the Busch Nicola Perscheid, has become something of a cult item,
particularly in Japan, receiving very high prices on the used market. There
were several series of P& S lenses, later sold under the Smith name only,
which differed in their characteristics. I don't know which was used as a
design basis by Cooke.

Speaking of used items, most are quite old, but there is less reason to
reject a soft-focus lens because of age than there is when searching for a
normal lens. O.K., it won't be as sharp as a new lens. You don't want it
to be. It won't be coated, and it won't have the contrast of later designs.
Most of your subjects will not want high contrast treatment. Flare could be
a problem, but that's what lens shades and lighting control are for. Many
soft-focus lenses have rather narrow coverage for their focal lengths and
this can be helpful where flare is concerned.

Still speaking of lenses which control the amount of softness only by the
aperture, there are many different designs which may be available at least
occasionally. One of the more common is the Wollensak Veritar. They have
an achromat pair at the back and a large meniscus lens at the front. The
combination gives a peculiar result in stopping down. All the gain in depth
of field is behind the plane of sharp focus, so instead of focusing on an
eye when making a portrait, you need to focus on the tip of the nose.
They are among the few older soft-focus lenses which came in (large)
synchronized shutters. 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. It may have been a Rapid Rectilinear type,
but more likely a Petzval.

The Kodak Portrait Lens is an achromat like those of the Imagon and Fujinon
lenses, but has a normal diaphragm instead of removable discs. The Spencer
Port-Land, the Hanovia "Kalosat" and the Cooke Achromatic Portrait are of
similar construction. The same description would also apply to early
"landscape lenses. The basic difference is that those intended as
soft-focus lenses have larger apertures.

Some Dallmeyer lenses fall into this grouping. One type was just called the
"Dallmeyer Soft Focus. It appears to be similar to the Kodak. Another was
the "Mutac", unusual in that it was a triple convertible. You could use the
lens complete or with either of the cells by itself.

The Petzval Portrait was a special case, not really a soft-focus lens, since
it is very sharp in the center. The very first mathematically computed
lens, it goes back to within a year of the public introduction of
photography and the aim was to produce a lens fast enough to take people
pictures. Softness in the outer areas was not intentional, but was accepted
in order to attain the desired speed. It also has an inward curving field.
Aside from wide-angles, most of the Darlot lenses found today are modified
Petzval types, some, the Ross, for example, offering a flatter field.
Burke & James were still offering new modified Petzval type portrait lenses
into the 1970's.

The other category consists of a normal lens, as far as the glass is
concerned, with a means of varying the lens elements so as to produce a
controllable amount of spherical aberration, thus giving you some measure of
control independent of the aperture. Stopping down will, of course, still
create a sharper image, but you have a degree of control over depth of field
in addition to amount of diffusion.

Here we go with categories again. Some of these lenses are based on
anastigmat designs, some are not. Those which are not are mostly Petzval
designs, and those most frequently seen are made by Dallmeyer, who started
making portrait lenses with diffusion control in 1866. You want shallow
depth of field? Try the Dallmeyer Patent Portrait No. 8D, 37" (934mm) focal
length, f6. If speed is your thing, the B series was f3. Most of these
well deserve the term "brass cannon". You need a very solid camera with a
large lensboard to make use of all but the smallest sizes. The glass ranged
up to 6" diameter. They were also extremely expensive, up to over $400 at a
time when you could buy an Eastman View Camera for $19.00. The smaller
sizes carried a rack and pinion focusing movement, and you had to pay extra
for an iris diaphragm instead of Waterhouse stops. Ross also made lenses of
this type in f3.5 aperture.

The Wollensak "Vitax" is probably a Petzval type. It was made in at least
three sizes from ten to 16 inches (254 to 406mm). It is distinctive in
having a knob on the side as the diffusion adjustment means. It may be
found in a "Studio" shutter, an iris diaphragm type working in only the
"Bulb" mode. Also apparently a Petzval type is the Eastman Portrait Lens,
not to be confused with the Kodak Portrait of much later production.
"Eagle" Portrait Lenses were sold by George Murphy Inc., and I think this
probably was a Murphy house brand. There were several series, both with and
without the diffusion adjustment.

Turning to the anastigmats, many makers provided at least a few lenses
with a soft focus adjustment added to lenses selected from their normal
production range. An exception was the Graf "Variable", designed from the
start as an adjustable diffusion type. The name derives from the fact that
the focal length and the aperture changed a little as the soft focus was
selected. Edward Weston was among the several prominent users of Graf
lenses. Wollensak made some lenses of this type, probably Tessars. The
ones I have seen were Series II, but there may have been others. In
England, they were made by Taylor, Taylor & Hobson (Cooke), Dallmeyer,
Beck and possibly others. Cooke lenses are the most common, in Series II,
f4.5 and Series VI, f5.6, but not all Series II Cookes have the diffusion
device. Many Cooke lenses have very prominent adjustment handles with two
finger openings, sometimes referred to as "spectacles". The absence of
these does not necessarily mean that there is no diffusion adjustment,
however. The only Continental anastigmats with a soft-focus feature that
have come to my attention are the Voigtlander "Universal" Heliar and the
Zeiss Portrait Unar, also made under license by Bausch & Lomb. There
probably have been others, though.

Like other tools, the use of soft-focus lenses improves with practice.
There is a problem in that the groundglass gives only a limited idea of what
the final print will look like. It would be a good idea to take a series of
otherwise identical photos with differing settings of aperture and (if
provided) diffusion control, when first trying out a soft-focus lens. The
resulting prints can then be used as references when making future
photographs.

There are many methods of softening focus without use of a special lens.
One idea, frequently suggested, is to diffuse the focus during enlargement.
There is a commercial item for this purpose, the Pictrol, too small at 2"
inside diameter to go in front of most large format camera lenses. The
problem here is that diffusion during a printing process produces a
different result. Diffusion onto a negative spreads light out into the
shadow areas. Diffusion during printing spreads darkness into the
highlights. The result has been described as being suitable for portraits
of the Addams family.

One early device mechanically jiggled the focus control during exposure, the
apparent aim being to increase depth of field. Some early lenses were
advertised as having great depth of field. This was the same as saying that
they were soft.

Some experimenters have used the rather hazardous means of partially
unscrewing a cell or cells of a normal lens. My first photograph with a new
wide angle lens produced a picture of a youth choir looking somewhat more
angelic than expected. I traced the phenomenon to a lensboard a little too
thick to allow the cells to fully come into position. As it turned out, the
choir director liked the result. If I were going to try something that
might result in accident to the lens, I think I would try it on one of the
surplus Xerox lenses. These are typically 8 1/4", f4.5, made by very good
manufacturers. As of this writing, Copy Raptars are available at
www.surplusshed.com at $10.00. The last I knew, these lenses by T,T& H, B&
L and Rank were available at www.candhsales.com at $16.50. The Raptars
appear to be normal production items, while the others were designed
especially for copy machines and may have been color corrected for the near
monochromatic light of these machines.

Some people have smeared vaseline onto the front of their lenses. I think I
would prefer to smear up a filter rather than a lens. Others have used
everything from cigar smoke to a piece of ladies stocking material in front
of the lens. In the latter case, sometimes holes are burned into the fabric
to modify the results. Hollywood types have employed fog machines. There
are commercial diffusing discs. 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..

There are ways of upsetting carefully calculated spherical aberration
reduction besides changing element spacing. A thick glass plate is one.
Adding various combinations of weak positive and negative elements, Proxar
and Distar and the like, might be another.

I have found surprisingly little in the way of compiled information on this
subject. This little article is an attempt to fill this apparent gap. All
comments, suggestions and particularly provisions of additional information
are especially welcome.


9 Risposte

Erg Frast

20/03/2019 08:43:25

0

Interessante, forse anche un po' pedante.
Non ho capito bene cosa intende qua:

> Diffusion during printing spreads darkness into the
> highlights. The result has been described as being suitable for portraits
> of the Addams family.

EF

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massivan

20/03/2019 12:16:21

0

> "Erg Frast (lab)"

> Interessante, forse anche un po' pedante.
> Non ho capito bene cosa intende qua:

> Diffusion during printing spreads darkness into the
> highlights. The result has been described as being suitable for portraits
> of the Addams family.

> EF


"massivan"

"Il diffusion (filtro) durante la stampa diffonde l'oscurità nella parte
piu' rilevante (dell'immagine) Il risultato è stato descritto come adatto
per i ritratti della famiglia Addams."

---------------------

C'e' il link per le lenti sfuse che fanno risparmiare parecchio volendo
imitare certi obiettivi.


massivan

20/03/2019 14:25:07

0

"massivan"

Ho impaginato il testo in PDF per la sua conservazione.
https://app.box.com/s/4004wrwzc6wgkr8a2i21ej...


Erg Frast

20/03/2019 14:32:03

0

Il 20/03/2019 15:25, massivan ha scritto:
> "massivan"
>
> Ho impaginato il testo in PDF per la sua conservazione.
> https://app.box.com/s/4004wrwzc6wgkr8a2i21ej...
>
>


Molto bene, già che ci sei riesci a trovare pure qualche ritratto soft
delle famiglia Addams, a titolo di esempio, perchè io non li ho trovati.

Grazie

EF

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massivan

20/03/2019 17:59:41

0

>> Il 20/03/2019 15:25, massivan ha scritto:

>> "massivan"

>> Ho impaginato il testo in PDF per la sua conservazione.
>> https://app.box.com/s/4004wrwzc6wgkr8a2i21ej...


> "Erg Frast (lab)"

> Molto bene, già che ci sei riesci a trovare pure qualche ritratto soft
> delle famiglia Addams, a titolo di esempio, perchè io non li ho trovati.

> Grazie

> EF


"massivan"

In effetti, di poco illuminata c'e' questa:
https://hookedonhouses.net/wp-content/uploads/2010/06/playroom-6...


Erg Frast

21/03/2019 08:29:55

0

Il 20/03/2019 18:59, massivan ha scritto:

> In effetti, di poco illuminata c'e' questa:
> https://hookedonhouses.net/wp-content/uploads/2010/06/playroom-6...
>
>


Qui c'è Morticia, ma mi sembra illuminata giusta:
https://it.wikipedia.org/wiki/Carolyn_Jones#/media/File:Carolyn_Jone...


EF

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massivan

21/03/2019 16:53:51

0

> "Erg Frast (lab)"

> Qui c'è Morticia, ma mi sembra illuminata giusta:
> https://it.wikipedia.org/wiki/Carolyn_Jones#/media/File:Carolyn_Jone...


"massivan"

A parte la chiave alta o bassa, questa e' una
bella foto.


Erg Frast

22/03/2019 08:39:35

0

Il 21/03/2019 17:53, massivan ha scritto:

>> Qui c'è Morticia, ma mi sembra illuminata giusta:
>> https://it.wikipedia.org/wiki/Carolyn_Jones#/media/File:Carolyn_Jone...

> A parte la chiave alta o bassa, questa e' una
> bella foto.
>

Certe volte si gioca facile.
Mi vengono in mente le parole di Elliott Erwitt Su Marilyn Monroe:
â??Era una donna estremamente intelligente, sensibile ed anche simpatica.
Era praticamente impossibile farle una brutta fotografia�.

https://fineart.ha.com/itm/photographs/elliott-erwitt-american-b-1928-marilyn-monroe-new-york-city-1956gelatin-silver-printed-later11-3-4-x/a/1917...


EF


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massivan

22/03/2019 21:44:05

0

> Data: venerdì 22 marzo 2019 9.39

> Il 21/03/2019 17:53, massivan ha scritto:

>>> Qui c'è Morticia, ma mi sembra illuminata giusta:
>>> https://it.wikipedia.org/wiki/Carolyn_Jones#/media/File:Carolyn_Jone...

>>"massivan"

>> A parte la chiave alta o bassa, questa e' una
>> bella foto.


> Da: "Erg Frast (lab)"

> Certe volte si gioca facile.
> Mi vengono in mente le parole di Elliott Erwitt Su Marilyn Monroe:
> "Era una donna estremamente intelligente, sensibile ed anche simpatica.
> Era praticamente impossibile farle una brutta fotografia".

> https://fineart.ha.com/itm/photographs/elliott-erwitt-american-b-1928-marilyn-monroe-new-york-city-1956gelatin-silver-printed-later11-3-4-x/a/1917...

> EF


"massivan"

Di Marylin Manru' (come dicono i veri anglofoni) ci sono molti
ritratti del genere "istananee" quasi rubate, ma quella della Jones
è un perfetto "ritratto formale", da studio, con luci artificiali, (non
quelle esistenti), robba da "fotografoni".