This week the challenge moves to a creative technique that can be used to make part of your image really stand out. Depth of field refers to the range of distance that appears to be in focus. The depth of field can be very narrow, with only a small part of the photograph appearing in focus. It can also be very deep, with objects in the foreground and background appearing in focus.
Notice the shallow depth of field in this image. The hand is in focus, while the neck of the bass is out of focus.
In this example, the depth of field is very deep. The heads of grain in the foreground and the trees in the background are all in focus.
Now, the question is: How do I change the depth of field? It’s simple! Just change the aperture. The aperture is the opening in the lens that allows light through to the film or sensor. The size of the opening is given as a number, referred to as an f-stop. Each lens will have its own range of f-stops. For example, the Canon 100mm f/2.8 macro lens has a range of f/2.8 – f/32, while the 50mm f/1.2 has a range of f/1.2 – f/16.
A larger lens opening will give you shallower depth of field. A smaller f-stop is actually a larger opening, so f/2.8 will be much shallower depth of field than f/11. Most cameras will have some way to control the aperture. Some cameras have an Aperture Priority mode that allows you to set the aperture directly. Some cameras have Scenes that will influence how the camera selects the aperture. If you are not sure about how to adjust the aperture on your camera, it might be time to dig out the manual or use Google. You can also ask a question on the PhotoChallenge Facebook or G+ pages.
Take some time to experiment with the aperture settings on your camera this week. Take the same shot with multiple aperture settings and see how it influences the photograph. Try to use depth of field to improve the composition and interest of your image this week.
Now go have some fun!
If you want to read more about depth of field, here are some links to get you started: