The View Up Here

Random scribblings about kites, photography, machining, and anything else

What Does “Group f.64” Mean Today?

Posted by Tom Benedict on 18/02/2015

Group f.64 was a group of seven San Francisco photographers who shared a similar approach to photography: well-framed photos with tack-sharp focus and lots of depth of field. Their style of photography was a distinct break from that of the Pictorialists, the dominant style in the late 1800’s and early 1900’s  that favored a more painterly look of soft focus, darkroom manipulation, and toned prints. Ansel Adams, one of the founders of Group f.64, referred to the Pictorialists as the “fuzzy wuzzies” because of their deliberate choice of soft lenses and relaxed approach to the technical aspects of their photography. His starkly beautiful black and white photography of the American Southwest was a strong departure from the work of the Pictorialists, and typifies the work done by Group f.64.

When I got into large format photography years ago, I read several of Ansel Adams’s books and read his take on the whole Pictorialist vs. Group f.64 debate. I was a fan of Ansel Adams’s photography long before getting into it myself, so I set myself on the path blazed by Group f.64. The only problem was that none of my 35mm lenses went to f/64. So I spent more and more time with my 4×5 view camera, and marveled more and more at the negatives coming out of the trays in the darkroom.

Which was great until I made the switch to digital. Oh I still have all my 4×5 gear, including several boxes of film I hope I can replenish when they run out. But 99.999% of my photography is now made using digital cameras. That takes me back to the question about my 35mm lenses. Why didn’t any of them go to f/64?

Setting aside the aesthetics of the debate of Pictorialist vs. Group f.64 (which was really the whole point, if you think about it), I wanted to see what it would take to make a photograph that, from a technical aspect at least, fit in with the Group f.64 manifesto. (That’s just a fancy way of saying I spent the better part of the afternoon playing around with an online depth of field calculator.)

To do this exercise it’s important to note a couple of things: First, I’m comparing cameras of different sizes. To make this comparison I assumed each would use the appropriate “normal” lens for that camera (typically a lens with a focal length about the diagonal size of the film / detector being used). Second, depth of field depends on the actual focal length of the lens, not what the 35mm equivalent of that lens is. This is important to remember when comparing cameras smaller than an APS-C DSLR. Finally, I’m taking the DOF calculator at face value. I personally disagree that the extents of what most DOF calculators call “sharp” are actually sharp by modern standards, but that’s a discussion for another time.

Let’s play!

The members of Group f.64 all used large format view cameras. Most typical at the time was the 8×10 glass plate camera. A normal lens for an 8×10 is generally accepted to have a focal length around 300mm. When focused to about 10′ at f/64 this gives a range of usable focus between 7.2′ and 16.4′, or about 9.2′ of DOF.

Despite the diagonal of a 35mm negative being about 43mm, the accepted normal lens for a 35mm camera is the tried and true 50mm lens. To get a depth of field comparable to that of a 300mm lens at f/64, a 35mm camera with a 50mm lens focused to about 10′ would need to be stopped down to f/11 to achieve a similar DOF (7.1′ to 16.9′, or about 9.8′ DOF). So that answers my question about why my 35mm lenses didn’t go down to f/64. To achieve the same depth of field as Ansel Adams or Imogen Cunningham I only needed to stop my lenses down to f/11!

My APS-C DSLR has a detector that’s 0.625 times the size of a full-frame detector (or to put it another way, a full-frame detector is 1.6 times the size of my APS-C detector). Going through the math, a lens with about the same field of view as that 50mm on the 35mm camera used above would have a 35mm focal length. Focused to 10′ I would need to use an aperture of f/9.0 to get a DOF similar to the 300mm at f/64 on the glass plate camera (7.0′ to 17.2′, or about 10.2′ DOF). This is interesting to note because the 18-55mm kit lens that came with this camera has a sweet spot around f/8.0 at which it delivers remarkably sharp images. Not too far off from that f/9.0 figure!

Just for grins I decided to run the numbers for my Canon Powershot A650 IS. Rather than run the numbers for a “normal” lens (10.3mm in this case) I ran the numbers for the widest focal length available: 7.2mm (35mm equivalent of a 35mm lens). Since the apertures on the A650 IS are limited, I ran the numbers with the lens wide open at f/2.8. Focused at 10′ I got a usable DOF of 5.15′ to 173.3′ or about 168.2′ total DOF (aka “a crapload”). And that’s wide open!

The moral to this story? Want to do photography in the Pictorialist style? Don’t use a compact camera! (Ansel would be so proud of me.)

Of course there’s more to the story than this. Group f.64 took a stance against soft lenses and soft focus. But more than that they took a stance against photomanipulation in favor of what they considered straight photography. (And you thought that debate started with Photoshop!) I hope photography has matured enough as an art form that we can have both in the same room without anyone coming to blows.

– Tom

P.S. Naaaaaah!

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