Adjusting the Depth of Field
Knowing how to adjust the depth of field is an excellent way improve the overall look and feel of a photographic image. When taking pictures, and adjusting the setting manually, it is a good idea to know what the depth of field is and how to adjust it. By adjusting the depth of field, it is possible to focus the image into a specific object while leaving other objects out of focus. Depth of field is the distance between the nearest and furthest object in a scene that appears in focus. There are multiple ways the lens settings and lens choice can affect the depth of field.
Focal Length of Lens
The shorter the distance from the front of the lens to the image sensor, the greater the depth of field will be. Essentially, more will be in focus in the image when using a shorter lens. For example, when using a wide-angle lens to shoot a scene, more will be in focus in the foreground compared to the background. On the other hand, a 200mm lens provides the ability to zoom into something close, while the depth of field will be very shallow.
|Narrow depth of field focuses in on the flower while everything else is a blur of green|
The f-stop setting will either increase or decrease the focal length. If the f-stop is set wide open or at a low number, the depth of field will be smaller. If the f-stop is set narrow or at a higher number, the depth of field will be able to be larger. Try this: take a picture with the f-stop at f2.8 and take the same picture at f22. It will be possible to see the difference in depth of field when comparing the two images.
Distance of Object
The distance between the object being photographed and the lens will also have an impact on depth of field. The further away the subject is from the camera, the further the depth of field will increase. When taking a picture of mountains using a wide angle lens, almost everything will be in focus. Yet, while using a macro lens, the camera is extremely close to an object, which will result in a very narrow depth of field in the picture.
|Using a micro lens to shoot a Foosball table, focuses the image into one player|
By adjusting the depth of field it is possible to narrow down and select the area that will be in focus in the final image. The result in narrowing down the focus of the image to what the photographer would like the viewer to see, allows the photographer to control the interpretation of the scene. By selectively using depth of field, photographers can create a professional looking effect which not only will make the images more enjoyable to view, but potentially more likely to sell.