Sunday, March 7, 2010

Hyperfocusing in Photography

What's the best way to get the entire scene in focus in a photo? Like most amateur photographers, I've always focused on the most distant point to do this. For example, to get a mountain and the foreground in front of it all in focus, I'd focus on the mountain. We learned in photography class, however, that this isn't the best way to get everything in focus. Instead is a technique called hyperfocusing, which sounds pretty technical, but it's actually not all that difficult.

The principle behind hyperfocusing is this: the range of a scene that your lens can focus on the most clearly extends 1/3 in front of and 2/3 behind the point in the scene that you focus on (aka the focal point). In order to decide on a focal point, you should pick a point that is 1/3 of the way from the closest point that you want to have in focus in your photo to the most distant point.

The following two photos of seven evenly spaced plant pots illustrate this principle.

In the first photo above, I used a shallow depth of field (large aperture and long focal length) to make the areas that are in focus easier for you to see. The flower hanging down on the side of the second pot was my focal point. Notice that the photo quickly goes out of focus both in front and in back of the flower, but that the focus is better on the pots behind the flower than it is on the one in front of it. For example, look at the third pot, and compare it to the first pot. The third pot is in better focus because it is behind the focal point (flower), even though it is the same distance away from the focal point as the first pot is. In fact, even the fourth pot is in better focus than the first one.

While the above photo illustrates the basic idea of hyperfocusing, it doesn't show you how to get the whole scene in focus. To accomplish that, in addition to hyperfocusing, you need to use a the greatest possible depth of field (smallest aperture and shortest focal length) possible. Doing this will maximize the amount of the scene that the lens can get into focus.
In the second photo, above, I focused on the same point, using a great depth of field so that as much of the photo as possible would be in focus. Notice how sharp it is from the closest pot to the furthest one. In addition, even the blinds way behind the focal point are in focus.Woo hoo.

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