Ansel Adams, Diffraction and F64

[Benson]

Regarding Ansel Adams and group f/64, I posted this to rec. LF last
november. I think individuals in this group might be interested in this
post too.

Benson

It's true, Group f/64 was in name only. The intent of this group of west
coast photographers were "Straight Photography" No soft focus, No
impressionistic interpretation of the subject matter. The original
members of Group f/64 were: Ansel Adams, Edward Weston, Imogen
Cunningham, John Paul Edwards, Sonia Noskowiak, Willard Van Dyke, Henry
F. Smith. Van Dyke suggested the name, "f/64" This name was chosen to
reflect the idea that f64 would deliver high resolution and great depth
of field when using a view camera. Ansel Adams felt that membership
should be limited to "those workers who are striving to define
photography as an art form by simple and direct presentation through
purely photographic methods." In November 15,1932. group f/64 sponsored
a exhibit with works from; Alma Lavenson, Consuelo Kanaga, Preston
Holder, Brett Weston at the M.H. De Young Memorial Museum in San
Francisco. The art world of Pictoralism after the exhibit was quite
shaken. William Mortensen a leading spokesman of pictorialist wrote with
anger in "Camera Craft" over the vision of group f/64. This battle with
Van Dyke and Adams lasted for a year and a half in Camera Craft. Later
in 1933 Ansel Adams opened a gallery on Geary Blvd. in San Francisco to
show the vision of Group f/64. Van Dyke continued to show similar works
at his Brockhurst gallery in Oakland, CA, 683- Brockhurst St. The Group
f/64 disbanded in 1935. The world of photography was never the same
after Group f/64. This group of individuals had a major influence on the
world of photography and art.

The Resolution of a lens depends on many factors. If we were not
interested in gathering a large amount of light on the film plane, a pin
hole camera would work fine. But this would make exposures very long and
the film under extremely low light conditions might not even record the
image. Film has a minimum light threshold. so we need a lens to collect
enough light to allow reasonable exposure times. Using a lens also
allows us to change the angle of view and perspective of a image. But
all this comes with a price, lenses have aberrations and other faults
limited by the laws of physics and the creativity of the lens designer
to work with these limits. Diffraction is one of them. I here is a
link; Photographic Resolution regarding this fact. It is oriented
towards 35 mm, But I think it's a pretty good explanation of
photographic resolution . On a view camera I never stop down past f45,
the resolution is too low. Resolution on film is only one of many
factors that determines how well a lens performs. In my images I try to
limit the enlargement factor to 5x. This allows a on film resolution of
aprox; 50Lpm. and a print resolution of aprox; 10Lpm. The human eye can
resolve aprox. 8-10Lpm under good conditions. I feel these are realistic
limits for modern film/lens/enlargement systems. Trying to get more on
sheet film is not easy under real world conditions. I have a
specification sheet for a areo recon. lens, 75 mm f4.5 Biogon. This lens
covers a 5"x5" sheet of film, using ultra fine grain, thin emulsion areo
recon film the resolution is aprox; 170Lpm at f4.5 across the entire
5"x5" image. But the lens itself will produce close to 400Lpm at f4.5 it
is a example of what happens when film and lens are combined together as
a system. This is a extreme case but under the condition they are
working with, this is what can be done. The best images do not always
have the greatest resolution, It's the content that really counts.
VILNTFLUID wrote:

> It has confused me that Adams and some of his friends were
> enthusiastic about
> stopping down to F64 for maximum sharpness and DOF.
> Aren't most lenses diffraction limited at apertures this small?
> Perhaps I did not understand correctly what the F64 group was
> advocating.
> Keith

[David Foy]

There is an article in this month's Atlantic Monthly about digital
manipulation (the ethics thereof) by an acquaintence of Adams. He tells much
the same story, adding the interesting bit that the original proposal was to
name the group US256 (the old "non-metric" American way of saying f64).
Adams felt it sounded too much like a highway, and proposed the then-new
"f64" equivalent.

--
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David Foy, 1431 6th St NW, Calgary AB T2M 3E7 (403)282-0512
Benson wrote in message <357501E1...@pacbell.net>...

[Michael Liczbanski]

> The world of photography was never the same after Group f/64.

I must say that your view of the world-wide importance of Group f /64 is a
little imperialistic (to use an ancient term) and definitely USA-centric.
There were many forces in photography at that time that had nothing to do
with f/64, and even though photography did take a dramatic turn around the
mid 30's, it can be attributed to other forces both in and outside
photography (the Soviet Constructivists, Bauhaus, the popularity of Leica,
the Great
Depression and many more.)

Just my USD .02.

Michael

[Fred Whitlock]

>
> > It has confused me that Adams and some of his friends were
> > enthusiastic about
> > stopping down to F64 for maximum sharpness and DOF.
> > Aren't most lenses diffraction limited at apertures this small?
> > Perhaps I did not understand correctly what the F64 group was
> > advocating.
> > Keith
>
>

To answer this simply-yes lenses stopped down to f64 (even those on view
cameras) suffer from diffraction loss. However, the large format produces
so much more detail than a smaller format that the diffraction loss becomes
relatively insignificant. It can be a big deal with 35mm but it really
isn't a big deal with large format. I use f64 very, very often because I
shoot a lot of small product closeups with 4X5 and a 210mm lens. I invite
you to come inspect my chromes. I think you'll agree that they are
breathtakingly detailed compared to what you would see with a 35mm camera
at any f stop. In other words it's all relative. Incidentally the f64
group wasn't advocating the use of f64, it's just that it describes them as
primarily large format photographers since f64 isn't used much (or even
available much) on smaller format cameras.
Good shooting.
--
Fred
Maplewood Photography
http://www.maplewoodphoto.com

>
>

[NYCFoto]

The difference in image quality between a LF lens shot at f22 and f 64 can be
great. Obviously if you need the DOF you have no choice but use a small
aperture, however most view camera leneses are optimum at around f22. In fact
Sinar will not allow you to use certain lenses, with their expolux or auto
aperture shutters, beyond f45 because they consider them unsatisfactory at that
aperture.
If you can get the image in focus at f22 or 32 you'll have superior optical
results.