Activity 1: Depth of Field


In this activity, you’re going to learn how to adjust the depth of field in a photo with Photoshop, by keeping only a small portion of the image in focus while taking the rest of it out of focus. This is a great way to bring attention to a specific part of an image and the effect is similar if you had shot the photo with a wide aperture.

This activity consists of three parts. Be sure to complete all three activities in order.


Depth of field (DOF) refers to how much of a photo is sharp in front and back of where you focus on the main subject. DOF is primarily controlled by aperture size, focal length of the lens and the distance the background is from the subject.

Deep depth of field means that all or most of the picture is in focus from front to back. It is often used for capturing subjects in the distance, such as in landscape scenes. The further away your camera is from the subject, the greater the depth of field.

Less depth of field means that a subject is in focus, but objects in front and behind it appear out of focus. Less DOF can be obtained when taking portrait and close-up pictures.


Students are expected to

  • work independently as well as in a small group (2-3 students)
  • capture with a camera a self created scene,
  • change the background in an image through photoshop
  • learn and apply depth of field to an image through photoshop


Part A: Capture a Scene

In the first part of the activity, students work in small groups (2-3 students), compose and capture a scene that consists of three different regions (foreground, middle ground and background).

The scene should represent:

  1. a foreground, middle ground and background
  2. a snapshot of an action such as people eating breakfast, students play soccer/basketball etc.,
    Take turns; each student should try to capture the same or another scene.

Save the picture in your activity 1 folder as: firstlastname_original_scene.jpg

Example of a Scene Snap Shot

Part B: Change Background of the Image
After you captured the scene, you are going to change the background of the picture with Photoshop. Choose any background that makes the scene more interesting (landscape, skyline, space, patterns etc.). You can capture your own background scene or take a picture from the Internet (make sure it is a free picture).

You can find free background pictures on the following links:

Example of a Background

Follow the step by step instructions in the video tutorial.

Save the background in your activity 1 folder as: firstlastname_background.jpg

Save the scene with the changed background as: firstlastname_scene_new background.jpg

Part C: Create a Depth of Field Image

Using the scene with the changed background, mask and blur out the different regions to create a replicated Depth of Field image “a la photoshop” (foreground, middle ground and background).

Step by Step How to Blur Different Regions on a Picture

Step 1:

  • Open your picture and duplicate it.
  • Go to the Tool Panel >Click Quick Selection Tool and select the foreground of your picture
  • Go to Edit >Copy Merged, Edit>Paste – the selected foreground is pasted on a new layer, label the layer as foreground
  • Do the same with the middle ground and background

Step 2:

  • Duplicate the scene layer and label it as “scene blurred”
  • Select the layer scene blurred”
  • To blur the picture you can either use the Box Blur or Lens Blur function
  • Go to Filter >Box Blur or Lens Blur
  • Now, you can add some Brush Strokes to the blurred picture in order to get a special effect.

Step 3:

  • Hide all layers except of the “scene blurred” and the selected foreground layer
  • You can see that the foreground is sharp while the middle- and background are blurred
  • Save the picture as a .jpg: Go to File>Save as>File name: firstlastname_dof_foreground>Format: JPEG
  • Do the same with the middle- and background

Save in your Activity 1 folder as:

  • firstlastname_dof_foreground.jpg
  • firstlastname_dof_middleground.jpg
  • firstlastname_dof_background.jpg
  • firstlastname_activity1.psd


Tutorial to:

  • Part B: How to Change the Background of an Image and
  • Part C: Create a Replicate Depth of Field Image

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  • Folder setup………..….. 2 marks
  • Saving Procedures ……. 3 marks
  • Task 1 ……………………. 5 marks
  • Task 2 ……………………. 5 marks
  • Task 3 ……………………. 5 marks