Depth of Field

Student filmmakers want their work to look like the professional Hollywood films they watch at the movies.

The DSLR revolution has made this possible but it doesn’t happen automatically. There are three primary things that students can do to achieve this look: shooting with a shallow depth of field, shooting in 24 fps, and color grading their footage in post. In this article, I will focus on how your classroom DSLR camera and interchangeable lenses can be used to get that shallow depth of field or “film look”. In order to master this you simply need to understand a few concepts.

Set Your F-Stop LowDepthofField
Aperture is a major factor in controlling your depth of field, but let’s take a step back. Inside your lens is an iris that opens and closes to control the amount of light that comes into the camera. This aperture is measured in F-stops; with the smallest number giving you the narrowest depth of field and the most light coming into your camera. So when you are trying to get that shallow depth of field, dial in the smallest F-stop your lens will allow. I like to pull out our old Nikon lenses that have a manual F-stop ring and let my students see the iris opening and closing as you adjust the F-stop.

Select the Right Lens
There is a reason that some lenses cost more and it usually corresponds to how low the F-stop will open. For example, a 50mm F1.4 might cost twice as much as a 50mm F2.0. So if you want to get that shallow depth of field the first step is to attach the right lens to your camera. The focal length of a lens also contributes to both the depth of field and how the distance between the subject and the background is compressed. For example, my students love to use our 300mm lens at full telephoto because of the way it both blurs and compresses the background. When we are conducting an interview the 85mm F1.8 lens is quite popular, and the 100mm F1.8 Macro is great for getting those dramatic close-ups. Check out this lesson on “How to Choose a Lens” for more on this topic.

Distance
The distance between the camera, your subject, and the background will also affect the “look” of your video. Simply moving your camera closer to the subject and the subject farther from the background will help creating that “blurry” background. Here is a one page handout that illustrates how to control your depth of field using F-stop, lens to subject distance and focal length.

Hands-on Activities
Here is a two day Depth of Field activity that will get your students some hands-on experience controlling their depth of field. I recommend extending this activity with the homework assignment because it takes quite a bit of practice to master this technique, and once they do their work will really start to achieve that “Film Look”.

Other Activity Ideas
Two Camera Interview: My students usually shoot interviews with our Canon XA10 video camera because of the excellent image quality and XLR inputs but we use a second DSLR shooting between 45-90 degrees off axis. Here is an example of our Superintendent talking about a new Scorecard Initiative using this technique.

LikethisAuthorDSLRTwo Camera Assembly: My students are often asked to film performances or speeches at our assemblies. Last year we added a second DSLR shooting from the side using our 300mm lens at full telephoto. The resulting shot is a nice blurry background of the students on the opposite side of the gym. Here is an example.

Bokeh Activity: This is a fun one day activity that will give your students additional practice controlling the depth of field in their shots.

Additional information
F-stop-Shutter – This is a nice one page handout that illustrates common F/stops and shutter speeds with tips on how they will affect your video.
CameraSim - This is a great web site that has two online simulations that allow you to learn about how your shutter speed, aperture and ISO affect your image. It is designed for still photography but the concepts universal.

At the beginning of the article I mentioned two other techniques student filmmakers can master to achieve the “film look” so I thought I would include some additional information if you are interested in learning more about these techniques.

Frame Rate
Film cameras shoot at 24 frames per second (fps) so if your students want their images to have the slight motion blur associated with film all they need to do is select this from the cameras menu before shooting. Here is an interesting lesson from the Vimeo Video School on “Setting up your DSLR” that covers this setting and much more.

Color Grading
Color grading is an art and would be a great way for your top students to push themselves to the next level. Here are a couple videos that explain how color grading work in the top non-linear editing solutions.

Apply Lumetri Color-Correction Effects to Your Sequences within Premiere Pro from Adobe TV
Final Cut Pro X - Color Grading from The Planet 5D Blog
Magic Bullet Looks - a color grading product by Red Giant


DockeryJoe Dockery teaches digital media courses at Mount Si High School in the Snoqualmie Valley School District, just east of Seattle, Washington. He weaves service learning into all aspects of his curriculum to ensure his students receive an authentic learning experiences. Dockery also consults and trains nationwide as an Adobe Education Leader. He has taught courses for Washington State University, Seattle Pacific University, The Puget Sound Educational Service District, and a variety of other school districts.

Awards
The Washington State Golden Apple Award
Radio Shack National Technology Teacher of the Year Award
Educator of the Year Award from the Snoqualmie Valley Schools Foundation ISTE’s “Best of the Best” 
ISTE “Making IT Happen”
Adobe Education Leader "Impact" Award
Pacific Northwest Key Club Advisor of the Year