How the Focal Length of Your Lens Affects the Look of Your Video

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."

Log in or register to post comments

9 Comments

Jonathan Krier's picture

This is some great information delivered quickly, accurately and more concisely than any other video on this topic I've seen on YouTube. I shoot interviews all the time, but when I first started out I had to figure this out as I went. This is a great resource for people in that position just starting out. Awesome job!

Mike Wilkinson's picture

Thanks for the compliment. It's easy to get caught up in tech if you go down the hole of field of view calculations and imaging planes, etc. I had to figure this out for myself as well! I used to love my Tokina 11-16 lens but turning my subject into stretch amrstrong was not good practice :-)

Alex Cooke's picture

"Vertigo" still has the best dolly-zoom. ;)

Mike Wilkinson's picture

Yes! It's definitely used perfectly given the subject matter. I think Jaws is my personal favorite though, love that film.

Simon Patterson's picture

I liked the fact you showed the distance to the subject. This seems to practically be the most important factor (assuming consistent framing of your subject), as sensor sizes and focal lengths vary so greatly. It appears that roughly a 5+ft distance between camera and subject worked best in your examples.

So maybe the interview framing rule of thumb could be called the "5 ft rule": ie use a camera/lens combo that allows a 5+ft distance to the subject whilst maintaining good composition.

I am primarily a landscape photographer not an interview videographer so am only surmising this from your vid here. Do you think my "5 foot rule" idea has merit?

Mike Wilkinson's picture

I like it! That would be a good distance to keep in mind when location scouting; knowing that you need an absolute minimum of 5 feet between your subject and the camera, plus some space to pull the talent off the background and space to operate the camera.

Often I'll set up more around 8-10 feet away as the talent can't even see the camera or the operator with the keylight in their face, and it makes it easier for them to forget the camera is rolling.

Philippe Cyr's picture

I know for myself as being the Camera guy/director and the one in front of the camera that I always try to set up roughly 6 feet away from where I am going to be standing or sitting for the segment I am shooting. Currently my equipment is what is holding me back as I have too much to carry in a case that is to small

Philippe Cyr's picture

I know for myself as being the Camera guy/director and the one in front of the camera that I always try to set up roughly 6 feet away from where I am going to be standing or sitting for the segment I am shooting. Currently my equipment is what is holding me back as I have too much to carry in a case that is to small

Philippe Cyr's picture

Sorry about the repeat comments, long day shooting the snow fall in my area