Controlling Depth of Field overview

Depth of field is the distance in front of and behind the subject that appears to be in focus. You focus the lens on one part of the image, the lens opening (aperture or f/stop) determines the depth of field. A large opening (f/2) creates shallow DOF with only one point in focus. A small opening (f/16) creates deep DOF with extended focus from near objects to distant object.

In this assignment you will use the aperture to alter the degree that your subject is in apparent focus. You look through your camera with its lens at maximum aperture, the smallest number of your f stops. This gives you the brightest view and facilitates focusing because at its widest aperture your lens has the smallest depth of field. What you see in the viewfinder is what you get.
When you "stop the lens down" or turn it to the smallest aperture, the depth of field is extended in front of and behind the distance where you focused. If your camera has a "depth of field preview" feature you will be able to see this change in the viewfinder. The image will get dimmer but the degree of sharpness will be apparent.
If your camera has a distance and depth of field scale on your lens, you will be able to calculate the depth of field to make sure the subject matter you want in focus is included.

If your camera doesn't have a depth of field preview and scale on the lens, you will have to go on faith that the effect will happen. Remember that the DOF extends in front of and behind the area you see in focus. To include two subjects in focus you need to focus between them.

Assignment requirements: Shoot at least one roll of film experimenting with shallow and deep depth of field. You should try a variety of subjects in varying light and at different distances to see what effect changing the aperture does to the image. Subject matter is your choice; Your image should include a subject or subjects that extends over some distance, you can't show depth of field with a flat subject therefore- Have something in the foreground and the background. Use a tripod, don’t move the camera, don't change focus between images, just aperture and shutter speed. As you learned in the motion assignment, you have to have the right lighting to accomplish this. DO NOT CHANGE THE FOCUS ON YOUR LENS BETWEEN THESE SHOTS! Do not try this part of the assignment in direct sunlight. With your tripod it can be done in fairly low light. Shallow depth of field is impossible to get in bright sunlight with 400 speed film.

Two Prints (5X7): Make two photographs of the same subject. One will show deep depth of field and the other shallow. These two exposures should be taken from exactly the same position - they should look the same except for the change in depth of field. Be sure to check your light meter to avoid over and under exposure. One 8X10 Print showing the strong effect of DOF (either deep or shallow) This doesn't have to be one of a pair - you can You will turn in your film log and contact sheets that show how much effort you put into this assignment. Make sure everything that you turn in is labeled. Name - Date - Roll # - Frame #

Exposure Calculation Wheel for download (pdf file) I have included a depth of field calculator on the site if you want to plug in the numbers and see what should be in focus. Photo One Home

Monday February 24, 2014