The ability to control depth of field is one of the most important creative tools you have, as different depths of field within an image will tell a completely different story.
Depth of field is one of your camera’s most useful creative tools and is vital for adding impact to your creative images. Before we can begin to figure out how to better control DOF, we must first understand the factors that DOF is dependent upon.
The main factor that controls depth of field is of course aperture. However, there are three other things that affect depth of field: the distance to the subject, the size of the sensor in the camera, and the focal length of the lens.
Set your camera’s exposure mode to aperture priority. Select a flower in the garden with some other plants in the background. You need to have more plants or something else in the background to get the most out of this exercise. Now set your aperture to its largest opening, which will be the smallest number, such as f/2.8. Take the photograph. Now go through each of your aperture settings, taking the exact same picture at each setting. When you have finished, upload the images to your computer and examine them in detail.
What you will notice is that the images with the largest aperture opening, such as f/2.8, have a shallow depth of field. That means the part of the image that is in focus is shallow. The background should be soft and out of focus. As you look through the images, notice that as you get to the smaller aperture openings the depth of field is larger, with more of the image in focus.
Once you understand how aperture works, you are well on the way to creating the artistic images you desire. This is the most complicated part. I recommend trying the exercise with each of your lenses to give you a really good feel for how it works with each lens you use.
Things to remember
- With careful composition, you can make out of focus subjects a meaningful part of your shot.
- Restricting depth of field in bright light isn’t always possible because your camera may not have a shutter speed fast enough to allow wide aperture. You can always use a neutral density filter to reduce the light entering the lens.
- When using shallow depth of field, be sure to focus carefully on the part of the subject you feel is most important.