In this article, I explore one of the most important photographic decisions you make in the field — where to place focus, and how to deliberately choose depth of field to convey information the viewer.
This article is part of a continuing series of thoughts on becoming a better photographer.
What is it?
Selective focus is a photographic effect made from making a deliberate choice about which part of a scene to render in focus. On the one end, you have scenes where everything is sharply in focus. On the other, you have a single object isolated against its background.
What does it communicate?
Selective focus can play several roles in an image. First, it can direct the viewer to the subject, or show the depth of the subject in better detail. It plays an editorial role: in-focus objects could be said to have primacy over blurry parts of the image. Sometimes a very narrow depth of field can create a sense of intimacy, exclusion, and solitude. Selective focus expresses the authorial voice of the photographer, since it is a deliberate choice. (In contrast, a scene with everything in focus often has the effect of removing the appearance of the photographer’s “voice” in the image.) As I’ve mentioned in other articles, having a narrow depth of field is very “photographic” and abstract — it is an effect that humans do not experience in the real world, since our eyes are so quick to focus on other objects. Sometimes removing detail information can direct the viewers attention to other relationships inside the image, such as lighting, texture or shape.
In this photograph, selective focus is used to enhance the abstract feel of the scene. Because the colors in the leaf match the background, the scene builds a dynamic tension between the sharply defined leaf and the background.
Here, selective focus is used to depersonalize the incense seller, and to create a strong sense of depth in the photograph. It draws the viewers attention to the pattern of the smoke, which is rendered very sharply into focus. Dynamic tension is created between the face of the merchant, and the incense around him.
In this photograph, focus is set along the narrow band of the cows face, just in front of the eyes. The angle of the photograph, and the separation of the cow’s head from the background add to the general message of confrontation between the viewer and the cow. The selective focus also draws the viewers eye to the matted texture of the cow’s fur. Inclusion of the ear tag, and leash, although indistinct in the background, offer an editorial hint that helps bring the viewer more directly to observing one essence of the cow: and animal, domesticated in the service of man.
How to get it
In the field, there are two main control levers you have to produce an image with selective focus: first, by choosing what to focus the lens on, and secondly, how much depth of field to set into your camera. In simple terms, depth of field is the result of what aperture you choose. Wider apertures (f/2.8, f/3.5) have a narrower band of focus that tighter apertures. Depth of field is a tricky beast — its the result of aperture, your camera’s distance to the subject, the focal length (zoom) of the lense and the size of your camera’s sensor. Depth of field is actually a very complex subject, governed by five different mathematical variables. To make this blog as practical and direct as possible, I’ll leave it to other sites to explain all of the mathematical relationships involved.
Instead, just bear the following rules in mind. All else being equal…
- The wider angle you go with your zoom lens, typically the deeper the depth of field. (This is part of what makes the movie Amelie so visually interesting — it was shot with an extreme wide angle lens.)
- The closer you are to the subject, the shallower the depth of field
- The smaller the sensor, the less depth of field
- The smaller the aperture setting, the wider the aperture, and the narrower the depth of field.
As I’ve often mentioned, the trick to executing this (and any other) photographic effect is to know your equipment well. You must practice to understand what combination of technical choices (zoom, aperture) will yield an image with a particular effect. When you’ve achieved a deep comfort with the look of certain settings (aperture, zoom, subject distance), it is much easier to previsualize at the moment you are holding your camera and trying to decide how to take the photograph.
Just remember that the technical aspects of selective focus (aperture, zoom, etc) are what give you the effect of selective focus. However, it is up to your vision as a photographer to choose these variables.
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