One aspect of depth perception not covered in my essay on depth The Third Dimension is depth of field.
Depth of field is covered for the photographer in a handy little summary in a booklet called How to Use Your Digital Camera’s Settings by David Schloss as follows:
“If you look at something near you …your eyes automatically adjust themselves so that only the objects you’re looking at are in focus. Switch to looking at a faraway object, and the eye automatically adjusts again, making the distant object instantaneously snap into focus while the nearby things fall into blurriness. Your camera, however, doesn’t have these limitations.
“In both of these cases, all the object within a few inches of the subject are in focus, but outside that range they get progressively blurrier. Our eyes have a shallow depth of field, meaning that the portion (depth) of our view (our field) that is in focus is relatively small…. Your camera doesn’t have this limitation, though, and, depending on the lens, the amount of your photograph that can be in focus at any one time can be vast.”
Now, there’s two points of interest here.
First, because we are so used to looking at the world around us, re-focusing as we shift our vision, we may forget to take into account focal length when painting from the world around us. While “focal point” as a subject is broader than this essay, certainly part of establishing a focal point in a painting depends on being willing to make some part of the canvas sharper (more in focus) than other parts.
Secondly, if — as many artists today do — we take advantage of the camera to record scenes that we can later paint at leisure, we may be forgetting that the camera is indiscriminate when set for wide-angle or point-and-shoot.
I am not one of those proponents of never using photography. It has a lot of benefits as far as I’m concerned, including not having to do battle with bees or weather the weather. But the limits of photography as source material for the visual artist, whatever medium you work in, should be kept in mind. One of those limitations is indiscriminate depth of field.