Today, manufacturers are touting fast lenses and large sensors. What this means for shooters and filmmakers is the ability capture images with less light and shallower depth of field. However, more and more I’m seeing shooters use the shallow DOF look just because they can. Some may chalk this up as creative license but I do believe there are some situations where a shallow depth of field is good to use and other times there isn’t.
When to use shallow DOP:
1. To create tension in a scene. A shallow DOF is good for creating a dramatic or tense feel for a scene. Often times these shots or close up or even extreme close ups on faces or objects your directing your viewer’s attention. This can create a tense feeling. You will often quick cut these scenes or to draw out tension even more by staying on someone’s face for a longer period.
2. To draw attention to a subject in your scene. This can be a person or an object. You could have one or multiple subjects in the frame and use shallow depth of field. If you do use multiple subjects, popular techniques such as rack focusing can be used to move your audiences focus from one subject to another in a single frame.
3. To create intimacy. Using shallow depth of field to create an intimate scene between two people is very effective. Be careful though. Too many times I’ve sean this effect used improperly. You can go too shallow! I’ve seen where the DOF is so shallow that part of people’s faces are in focus but the far side of their heads are not. This creates a huge problem especially if your subjects are moving, like dancing. Make sure if you’re going to open up your aperture that you don’t open up too much where you only have portions of your subject in focus. To keep your audience focused and in tune with the mood of the scene, make sure your subjects are clearly in focus.
Side note: I will be talking about some mobile apps that will help you dial in the right aperture for your scene in order to eliminate these mistakes.
Ok, we’ve talked about some situations in where it’s proper to use shallow depth of field. Now, let’s look at some situations where it’s not.
When not to use shallow DOF
1. Instructional content. This has to be one of my pet peeves. To watch an instructional video on how to complete a task and the shooter uses a wide open aperture, so much so that the person giving the instruction has to move the object forward and backward in order to achieve proper focus. This is a bad use of shallow DOF. For one, it gives your audience headaches! Trying to focus on objects of an instructional video will drive you audience away. Think as if you were looking at the scene in person. You will try to take in all the information you are showing in the frame. Having shallow depth of field forces the viewer to only look at one part of the object, and sometimes not the complete object. Your audience wants to feel as if you were there with you showing them the instruction. Using shallow DOF does not accomplish this task effectively.
2. To reveal a location. By nature using wide lenses will give you less depth of field. However, I’ve still seen shooters reveal a location only to have objects in the foreground and background still out of focus. There are exceptions to this rule such as using foreground objects to give your scene a sense of movement such as slider moves, track and dolly or jib movements. But for the most part, to put your audience in a particular setting, using a deep depth of field is most effective.
3. Tracking/Action shot. Your subject may move from the foreground to the background and vice versa in a single shot. Especially when it’s moving quickly, as in an action shot, you’ll want to keep your AC happy and not create a shallow depth of field. Now this doesn’t mean your AC can just go take a coffee break for this take. He will want to still rack focus but the movement will be minimal with deep depth of field. This also allows your audience to better track with your subject as they move within the frame.
So there are some examples of when and when not to use shallow depth of field. Of course there are exceptions to every rule but these are more technical rules to keep your audience engaged rather than creative suggestions that can be subjective.
What are some situations in which you use or not use shallow depth of field?
For an understanding of aperture, Nikon has a nice page that runs through the basics. Even though it pertains to still photography, the basics still apply to motion picture.