Image taken on Nikon D5000. Shallow depth of field to blur the background
Image taken on Nikon D5000. More depth of field to ensure a sharp, end to end image
Aperture priority is one of the settings on a camera that usually stands for “AV” or “A” on your spin dial. Aperture priority and depth of field goes hand in hand and is at first, a hard concept to grasp. Basically, you have the more common apertures of F2.8, F5.6, F8, F11, F16, and F22. In order to gain the more depth of field you want to be set at F22 to give you the most sharp picture from end to end. In order to achieve a shallow depth of field, you want your setting to be set to F2.8.
The best time to use a shallow depth of field would be when you want your background to be out of focus. A perfect example of this is when you are taking pictures of a flower. Using your focal points in your viewfinder you want to set the main focus on the flower so your background is soft and out of focus making the flower the sharpest in the image. A good setting that I enjoy taking my flower pictures at is F2.8 or F5.6 so I can ensure the background is completely out of focus and making sure the flower is the sharpest. Another example of when you want a shallow depth of field is when you are taking portraits. If you have your subject in a very busy background such as in a school setting, you want to blur out the background behind the subject so the background does not take away from your portrait. A great setting for this would be F5.6.
A time where you would want to use a great depth of field ensuring your entire image is in focus is in landscapes and product photography. The reason you want a sharp image for these two types of photography is because for landscapes you do not want to show any blur to the image because generally speaking, if clients are going to purchase your image, they want a sharp end to end photograph of the landscape. The reason you want a sharp product shot is because if an advertising agency is going to hire you, they do not want their product to be out of focus because they are trying to promote their product through captivating images that a photographer can produce. For both Product and Landscape photography I like to make sure my F stops are set to either F16 or F22 to ensure that the end result is sharp.