How To Make Spectacular Photos With Selective Focus
Selective Focus is a great technique that helps you ensure you're able to direct the viewer to the primary focal point (e.g., subject) within the frame, rather than to similar elements which might otherwise compete for their attention. I made the above photo, to demonstrate this technique, in the gardens of Versailles on a warm summer's day.
Let's look at how to apply the selective focus technique to your images.
- Ensure the lens is focused on your primary focal point. You can employ focus peeking, if your camera includes that feature, to achieve more critical focus on stationary subjects.
- Employ a shallow Depth Of Field to de-emphasize the surroundings and, thereby, make your primary focal point stand out against a de-focused background.
How To Create A Shallow Depth Of Field
Folks often complain to me that they're unable to blur the surroundings to the degree they'd like to. The reasons for this are a little complex, although the solution is, sometimes, quite straightforward.
The three factors that determine Depth Of Field are aperture, focal length and camera to subject distance. Let's examine each of these factors, one at a time.
Aperture Makes Photos With Amazing Depth Of Field
A physically wide aperture, such as f/3.5 (or wider), will produce a relatively shallow Depth Of Field. The smaller the aperture (i.e., f) number the more shallow the Depth Of Field should be.
I made the image directly above by critically focusing on the eyes of my primary subject, a lovely lady in Beijing, and employing an aperture of f/4 to place emphasis on her by rendering all the other dancers out of focus.
Conversely, a physically narrow aperture, such as f/11 to f/22, will produce a large Depth Of Field.
The image directly above, made at an aperture of f/11, allowed me to render all of the image, from the immediate foreground all the way to the distant background, nice and sharp.
Think of focus as a measure of distance. The sharpest part of an image will always be the exact distance at which your lens is focused. Depth Of Field is an impression of sharpness both in front and behind the actual point of focus (i.e., subject).
Lens Focal Length And Its Impact On Depth Of Field
A wide-angle lens (e.g., 18 mm) will produce a larger Depth Of Field than a more powerful focal length (e.g., 55 mm) would at the same aperture and camera to subject distance.
The photo immediately above was made at a focal length of 24 mm at an aperture of f/16 on a Nikon D800e full frame camera. As well as the wide angle of view produced by the 24 mm focal length the Depth Of Field in this image is huge.
Conversely, the close up image of a King Penguin's feet on Cuverville Island in Antarctica was made on a full frame Canon 5D Mark II camera with a Canon EF 100-400 mm lens at a focal length of 400 mm and an aperture of f/5.6
The Depth Of Field in this image is incredibly shallow as evidenced by the penguin's left foot being sharp while almost everything else in the image, including it's right foot, has been rendered out of focus.
How Camera To Subject Distance Changes Depth Of Field
The closer you get to your subject the more quickly the surroundings (i.e., foreground and background) will fall out of focus. Conversely, moving further away from your subject, and then refocusing your lens, will increase the Depth Of Field.
Both the images directly above and below were made with the same lens. While the aperture is somewhat different, the main difference is in the camera to subject distance and how that effects Depth Of Field. I think you'll agree that this comparison shows just how profound that difference can be.
One of the problems folks have achieving a shallow Depth Of Field is due to the fact that the lens they use (probably a kit lens) does not have a particularly wide maximum aperture. Whilst f/3.5 is relatively wide, apertures of f/2.8, f/2 or f/1.4 will produce images with significantly shallower Depth Of Field with the same camera, lens focal length and at the same camera-to-subject distance.
Furthermore, the maximum aperture associated with most kit lenses varies with the focal length. As you zoom in, to bring the subject or scene closer, you loose the ability to gather light. As a result the lens's maximum aperture is reduced from, for example, f/3.5 to f/5.6. While zooming in should, in theory, create a more shallow Depth Of Field the resulting loss of maximum aperture, from f/3.5 to f/5.6, may well prevent that from occurring.
In this case you're probably best just moving in closer. It's a great solution which, to all intensive purposes, appears non-technical. And that's the beauty in it, wouldn't you agree?
If you live in or around Melbourne, Australia and are interested in learning more about how to use your camera to make really great photos be sure to click the image above for details on a special one-to-one private photography class with me. The price has been lowered, but only for a short time.