Depth Of Field

Barley, a dog, is photographed up close, such that the lens keeps her face in focus, but her body is slightly out of focus.

It’s second nature to me now that the third dimension can be read, at least in closeup shots, by attending to the focus of the photograph. But I have to wonder, is that something I had to learn? Clearly, our own eyes adjust the focal depth all the time, so reading three dimensions into a two dimensional photograph that relies on the same optics isn’t exactly rocket science, but I can’t turn my eye to something in my own visual field and not have the focus automatically adjust. With a photo (or a movie), your eye can linger on things out of focus for as long as you like, providing an experience that is specific to these externalized optical records. At some point, I presume, I must have come to understand this about photos, but it must have been very early in life, perhaps even before my earliest coherent memories.