Have you ever seen those amazing shots that show a subject holding its place in the frame while the background falls away or becomes extremely compressed? This is called a "dolly-zoom," and you've likely seen an example in films such as "Jaws" and "Goodfellas." While we don't typically use a dolly-zoom when filming interviews, we can learn a lot from studying what happens to an image at different focal lengths. In this video and article, I'll discuss the visual effects created when choosing a wide versus telephoto lens for documentary-style interview productions.
In the last few weeks, I wrote about location scouting, and then picking a frame for documentary-style interviews. Continuing with the theme of producing interviews, today we’re going to take a look at how using different focal lengths manipulate the visual relationship between your subject and background, along with some examples of where distortion can set in.
Note: In the following paragraphs I will be referencing focal lengths, but know that your results may vary from lens to lens or camera to camera.
While using wide-angle lenses can be helpful when working in tight spaces, especially when filming B-roll for a project, rarely are they an ideal choice for capturing interviews.
An average interview framing usually places a subject in a medium closeup shot. With a focal length of less than 28mm, not only will you have to stand very close to the subject, but if the subject approaches the edges of the frame, it’s quite possible that barrel distortion or keystoning may happen to parts of their body. Facial features can become exaggerated, and that’s usually not desirable. Here is an example.
Another byproduct of using wide-angle lenses is how much more apparent the background becomes. It can appear further away, and your viewer will be able to see much more of the surrounding location. This isn’t necessarily a good thing or a bad thing; revealing the background might include important contextual elements to the story you’re trying to tell. In the case of live interview segments for programs like sporting events or news, it’s not atypical to see the camera very close to the interviewee, as sometimes space is very limited, or there are multiple news crews all fighting for attention from a person of interest.
Focal lengths between 35mm and 50mm can be a "safer" choice when you still want to include some of the background, or don’t have a large space to work in. The background will compress a bit more, facial features won’t be as exaggerated, and distortion will be less apparent, especially the closer you get to 50mm.
My go-to choice for most documentary style interviews is usually between the range of 70mm and 110mm, depending on the space and how much background I want to show. Longer focal lengths can create a cozier feel to an interview, and reduce visual clutter. Proportions in an interviewees face will appear normal as well. I like this range also because I can place the camera far enough from the interviewee so that the camera setup isn't as imposing or distracting, and they have an easier time focusing on telling their story to the interviewer.
Longer focal lengths of 135mm and beyond might look great for a tight closeup framing, but you’ve got to be careful as you will need to start backing up significantly from your subject if you don’t want such a tightly framed shot.
While I enjoy using prime lenses, I do find myself often choosing a zoom lens when framing up my master interview shot. This lets me audition a few different focal lengths (without changing lenses) while physically changing the distance between my camera and the subject to create slightly different looks. I find that for a 2-camera interview shoot, my lens kit will include a 24-70, 70-200, and an 85mm prime. These lenses should provide me with all of the options I need for both a medium shot and a closeup.
If you’d like to learn more about techniques to improve filming documentary-style interviews, check out my e-book, "Tips for Shooting Professional Video Interviews."