Before cameras, did artists grasp the concept of things being "out of focus"?

I was looking at John Trumbull’s Declaration of Independence and realized why the painting may have seemed a bit off to me: you’ve got some people in the foreground and others in the far background, but all of them are perfectly in focus. This is especially noticable if one zooms in on where the background and foreground are adjacent, like here. Adams looks like a giant compared to the puny bewigged guy right behind him.

Of course, in a painting like this one, Trumbull would have wanted all the faces to come through clearly anyway. But in the days before cameras, would he or other artists even be aware of the artificiality of such an image? Did anyone back then try to represent blurriness beyond a painting’s focal point?

“Depth of field” was pretty much unknown before cameras. Perhaps things like spectacles or telescopes could emulate it, but probably not, as the human eye would adjust.

Myopia notwithstanding, what the eye is trained on is usually in focus, and any shift to a closer or distant object would be instantly focused again, naturally. It would be impossible to train the eye on an out of focus part of your field of view.

So it was an alien concept, and wouldn’t have been represented in art.

Trumbull certainly didn’t paint that picture with an eye toward viewing it on a flatscreen monitor 12 inches across. You weren’t ever meant to take in the entire thing in the same plane of focus; the real painting is 12 by 18 feet, not inches.

So perhaps they didn’t acknowledge depth of field, as a camera would, but it would have been unnecessary. The medium was a bloody big canvas; methods of miniaturizing and creating reproductions were limited. On the original, if you were looking at Thomas Jefferson, then Samuel Adams would be out of focus because he wasn’t in the center of your vision.

:confused: He might be relegated to my peripheral vision, but surely he would still be in focus?

And the thing is, I don’t really notice when it’s on my small monitor screen. It’s only when I really zoom in to look at it a portion at a time that I notice how unnatural the transition is between foreground and background. So unless you were standing really far back away from it, woudn’t it actually be more noticable with a huge painting like this?

That’s not completely true. If you hold something really close to your eye – say an inch or so (closer if you’ve got good eyes), you can’t focus it, no matter how hard your eyes try. your eyes sdon’t have infinite adjustability.

I’ve argued that ancient people could’ve used tiny apertures – holes punched in ceramic, leather, shell, wood, or whatever – to make devices that would let them get things closer to their eyes. They could then see them better, and in more detail. They’d be de facto magnifiers, since the objects would subtend a larger angular field than they would when held at a “comfortable” viewing distance. In the absence of some clear glass or pure crystal, and a lot of work at grinding and polishing, this is a really good and quick and easily fabricated substitute for a lens.

Doesn’t a small aperture emulate a concave or plano-concave lens, rather than a convex magnifying lens?


I don’t understand what you mean by this. An aperture by itself has no optical power. By eliminating many of the incoming rays, however, the pinhole can eliminate the blurring you get when an object is held too close to your eye to focus something.

When you say “cameras” do you include camera obscuras (which is what Cal Meacham is talking about (ETA-- on rereadind, we’re talking about different things-- sounds like he’s talking about something like a Leeuwenhoek microscope?))? We know Canaletto owned one, and Vermeer may have seen/used/been dependent on one (depending on what author’s research you buy into). They didn’t magnify per se (well, they projected) but they do work with focus and such. I can give citations to some arguments that optical effects caused by depth-of-field issues with a c.o.'s focus are reproduced in Vermeer’s work.
Leonardo’s ‘sfumato’ isn’t exactly meant to emulate lens focus, but the effect is similar.

The Mona Lisa is famous for keeping the lady in focus while making the background progressively more blurry the farther it extends from the subject.

This is a testimony to the genius of Leonardo. It also demonstrates that the concept of focus was indeed known during his time, about three centuries before the daguerrotype was invented. It also predated Johann Zahn’s portable camera by nearly two centuries. The camera obscura, on the other hand, predate Leonardo by several centuries though.

What I’m talking about is neither a Camera Obscura (in which a pinhole is used to create an inverted image in a darkened room ( "Dark Room " = “Camera Obscura”) nor a Leeuwenhoek microscope (which uses a lens for magnification)

The center of your vision is courtesy of the macula, which is far more acute than your peripheral vision. When you focus the center of your vision on something, everything else is blurry by comparison — perhaps not “out of focus” by the truest definition of focal length and distance, but certainly not in sharp relief. It simulates much the same effect.

That aside, it is still difficult to conclude that “because paintings were always in sharp detail, primitive people didn’t understand focus.” Art is not a perfect near-photographic reproduction of the artist’s world, but a product to be sold; and products are governed by the rules of the market. In about 1850 in the Western world, this meant most paintings were of the Mythical, Portrait, or Religious paint-what-you-know-is-there variety, dominated by the Académie des Beaux-Arts and the opinions of critics. If you didn’t paint their way, essentially, you weren’t given space at the prestigious art shows.

It wasn’t until the Impressionists came along that you started to see other artists, other methods, and scandalously inappropriate subject matter of the paint-what-you-see variety: paintings of prostitutes, outdoor still lifes, blurs of vibrant color, and so on.

It’s not really fair to examine art of a certain period and say “they didn’t understand X.” You wouldn’t look at Cubist art and say “primitive people didn’t understand perspective.” They painted that way on purpose.

IIRC my art history classes, it was the Dutch/Flemish renaissance period that, for outdoor scenes, popularized the realist technique of backgrounds getting hazier and the colors getting bluer with distance and haze. It wasn’t really related to focus plane however.

By the way, there was that big controversy about eight years ago when Davis Hockney and Charles M. Falco dared suggest that Vermeer and other artists used the camera obscura and other optical devices as an aid to getting perspective right. The dispute was pretty bitter, and there was, in my opinion, a lot of misrepresentation of arguments by the opposing sides. It certainly wouldn’t surprise me that they were used. Heck, when the Camera Lucida was invented, that’s exactly what they did with it – and continue to do in aret classes to this day.

In any event, Hockney and Falco argue that, as a result of using these devices, some optical aberrations crept into the paintings, and are still discernable if you know how to look for them. If so, the artists probably weren’t aware of them at first, but would have noticed them with time. This would be well before the invention of photography.

Sure, but camera obscura images are pretty damn near hyperfocal due to the tiny apertures, are they not? There really wouldn’t be much depth of field effected by using a camera obscura.

Even with a pinhole, camera obscura images aren’t perfect. And you can make much brighter images if you use a lens in place of a pinhole. Hockney and Falco do claim that they used a lens, and they even claim to be able, in individual cases, to be able to determine its aperture and focal length.

Sure they’re not perfect, which is why I cautiously used the term “damn near hyperfocal.” Still, from what I’ve seen of camera obscura pictures, pinhole photography, and all that, we’re dealing with apertures of like f/128+. What kind of apertures are Hockney and Falco getting for the lensed camera obscura images? (edit: that would actually be the camera lucida, right? Which didn’t show up until about the 1800s.) Unless we’re getting apertures of below f/11 or so (depending on where the focus is), any depth of field effects will be very, very minimal.

I don’t have any of the papers with me, so I can’t tell you exactly what they used, or what f/# they thought they had. They were claiming Camera Obscura use – this was stuff dating from the 16th century – and not the Camera Lucida*.

  • I wrote an article on the invention and use of the Camera Lucida by Wlliam Hyde Wollaston – who came up with it because he couldn’t draw – sometrime between 1800 and 1806. It’s in Optics and Photonics News for this month (July/August 2008). Ironically, one of the inventors of Photography – William Fox Talbot – did so because he was incapable of using the Camera Lucida.

There are claims that the Camera Lucida was invented much earlier, but these don’t stand up to examination. And the use of “Camera Lucida” before 1800 refers to something completely different.

Now that 1800s camera lucida, it would have a shallow depth of field from what I understand, right? Would artists refocus it to draw different parts of the image typically, or am I not understanding the concept of a camera lucida correctly?

Wait wait. . . in my understanding of the classic camera lucida, there’s nothing about a lens or focus or anything, but rather a prism redirection of the gaze so that the subject and paper drawn on are optically overlapped or superimposed. Are we talking about something else?

And the Vermeer/camera obscura thesis goes back way before Hockney, and IMO was argued better and without the ridiculous red herrings of Van Eyck and whoever the hell else (see Wheelock, or Steadman for example). The theory was that V was using a closet-type c.o. built on one side of his studio-- there would be a pinhole (or arguably a lens-- he and Leeuwenhoek were active in the same town) in the wall toward the posed subject, and he could trace on the far wall of the cabinet. This, it’s argued, can account for optical oddities in his work such as the unusually strong perspective in some scenes (the indoor scenes with an object in the near foreground), apparent orbs or ‘circles of confusion’ where highlights weren’t in focus, and the highly standardized presentation of his interiors. It’s a reasonable theory, but Hockney took it further than it needed to go.

I think it’s me that’s confusing it with something else. A camera lucida doesn’t project anything, from what I’ve since read up on. And it basically does seem to be a prism redirection. I was completely imagining it wrong.