What Is Focus Breathing In Film Production: A Complete Guide

Focus breathing is the term used to describe what happens when you adjust focus while filming, and it refers to the focal length of a lens expanding or contracting.

The problem with focus breathing is that it makes the frame feel like its zooming in, even though your camera isn’t actually moving.

This can look really bad if you’re trying to film something and you have to zoom in and out to adjust focus.

Focus breathing is a phenomenon that can be annoying for filmmakers and photographers.

It’s caused by the fact that many lenses allow you to change focus while shooting.

This changes the position of the lens elements, which in turn results in a change of focal length.

Let’s dive right in!
 

What Is Focus Breathing?

Focus breathing, also called “lens breathing”, is a common phenomenon in film production. It is one of the biggest complaints some viewers have about movies.

The term was coined by a documentary filmmaker, John Hoke. The concept of lens breathing has most commonly been associated with the idea of a zoom lens drifting in and out of focus due to temperature changes.

It is similar to a rolling shutter in photography, where moving objects appear to teleport from one place to another and back again. 

In film production, focus breathing is the effect of changing the focal distance of your lenses during a shot.

Focus breathing in film production intends to achieve the correct, natural brightness and darkness through camera angles and lighting. Focusing is integral to good film production — even more so than what exotic, expensive technology is used for.

   

Why Lenses “Breathe” In Film Production

One of the most important revelations a filmmaker learns early on is that every lens has breathing. It is caused by some physical factors that are intrinsic to using the lens itself and can be properly managed for its use in certain effects.

For those of you who don’t know: one of the reasons lenses “breathe” is because they have an opening in the center which allows air to pass through the lens.

This is important because it allows the lens to adjust to the air pressure inside, and helps prevent fogging on your lenses.

In layman’s terms, breathing means “focus breathing”; this occurs when focusing at one distance induces optical expansion or shrinking, and changes in depth of field (or DOF). Although it seems like you can focus on the same distance while zooming or refocusing the focal length, the lenses expand and contract.

Additionally, the focal distance is relative to approaching or backing away from the subject focused within the frame, or changing your position relative to the subject before pressing the shutter release button.

Interestingly enough, this concept is not exclusive to lens adapters or vintage lenses. The phenomenon applies to all lenses, whether they are old or new.

However, with understanding comes opportunity. With a solid knowledge base surrounding DOF lenses, filmmakers have many creative choices to create a unique look for their films.

What Is Lens Breathing In Film Production

People who are in the film production industry will speak of lens breathing. It is an optical phenomenon in filmmaking wherein the angle of view of a lens changes slightly as you focus throughout the film’s focal range. 

To put it simply, lens breathing happens when the lens moves while the camera is filming.

It is also the term used to describe how much a lens moves when the camera’s focus remains locked on the same point. This helps compare how a lens will react in different situations and it also helps determine what types of shots will be best suited for which lenses.

This phenomenon is most apparent with long lenses but can also happen with wide-angle lenses up to a certain point. If this occurs during filming, it will result in a jump cut, which is an unsettling visual glitch that can ruin your footage.

What Is Focus Breathing Compensation In Film Production

For a while now, we have been hearing people throw the term focus breathing. It’s a term used by cinematographers on a film set and often brings an undesirable effect for many reasons.

For example, with certain shots, there is a need to have the background in focus even when the foreground is in motion or vice versa. Also, it can make it difficult for on-camera talent or co-workers to speak to each other if one is far from the other.

Focus breathing shows how the apparent size of an object changes as you focus your camera on it; it could either make or break a shot.

Let me show you what I mean… Focus breathing is a visual illusion that occurs when you shoot with a long focal length. The result will appear to change as the subject moves closer or further from the camera.

When shot on a 400mm f/2.8, our focus breathing demo reel shows the difference between having automatic focus breathing compensation turned on, and turned off (a good idea if you possess the ability to control it).

Is Focus Breathing A Big Problem  In Film Production?

Where there is a film or video production crew, there’s often a lot of equipment. Sometimes, things get confusing as to who is responsible for what.

How can we avoid the old “he said, she said” routine? Let’s discuss one sensitive area that often causes problems: focus breathing.

   

In practice, it may be tricky to control. Focus breathing can cause problems with editing and continuity because it changes the apparent size of the shot. 

You got your Polar Bear, who is your director. And they are telling you to hurry up because you are supposed to be shooting when the sun comes up.

Okay, you set up a simple 2-shot and the actor is breathing heavily. Easy fix, right? Change the lens, keep the same focus, adjust the light if needed, shoot, and you are done, right? I mean, how bad can it be? 

Stay focused and help your actors stay in the moment by taking a few deep breaths before starting each and every shot. This will help with your production scheduling and keeping your set calm.

Does Focus Breathing Matter In Film Production?

Regardless of the problems with focus breathing, understanding how it works could revolutionize your filmmaking. But does it matter? This article explores this question, by drawing on examples from various filmmakers and pointing out some key differences.

The purpose of focus breathing is to provide the film with the desired amount of motion blur. When you follow your subject and zoom in or out, you are essentially controlling the focus breathing, and keeping everything in focus.

It is a technique that gives a balanced look between the foreground, middle ground, and background. It gives your footage more depth, energy, and life.

This video focuses on the benefits provided by focus breathing in film production. 

The character of focus breathing is largely a divisive subject among lens users. Some feel it matters, and others feel it doesn’t.

While most deep-focus aficionados will tell you that the former argument is correct, we’ve discovered that most working cinematographers have their secret tricks for minimizing focus breathing when shooting on set or in fast-paced environments. Many film directors teach that the camera should be on a tripod.

The idea itself is to aid in making sure the framing is correct and that focus can be obtained quickly with fast-moving subjects. On the other hand, some film directors do not like this idea and think it is dumb.

They prefer to have their camera on a shoulder rig with no tripod at all. Some even go as far as saying that their way of filming is the best and everyone else should follow suit or one will never become a true film director.

Where does the truth lie?

Focus Breathing In Cinema Lenses

Focus breathing is a technology that allows the focus to move in movie scenes for a much more realistic and enjoyable viewing experience. Lenses using this technology create a sense that actors are actually moving closer or further away from you as if you are standing next to them in a movie theater.

This webinar describes how focus breathing lens design works. Focus breathing is an optical look that emulates the shallow depth of field and compression effect as seen when shooting on a 35mm film.

This look is achieved through contrast adjustment in the lens to create a look that makes the foreground subject pop off the screen while maintaining a consistent focus plane. 

Focus breathing also helps to emulate human vision. When we watch movies, our eyes focus on where we want them to go, giving us an immersive experience.

Focus breathing is an optical characteristic that indicates lens breathing, or the change in apparent size as a function of focus. Focus breathing lenses have been optimized for use on motion picture cameras.

They are often available in larger focal lengths with T2-weighted contrast levels and long working distances, which are best suited for cinematography.

Focus Breathing Is A Common Issue On Most Photographic Lenses

Focus breathing is a common issue with most photographic lenses. This is when out-of-focus areas in your image change in size ultra-wide as you stop down your lens.

For some photographers, this can add a creative flair to their images. Focus breathing is what happens when a lens’ focal length changes slightly as you focus.

This can cause elements in the image to appear to zoom in or out as the depth of field (DOF) changes. The effect was especially pronounced on early ultra wide-angle lenses and certain fast or wide-angle primes, most of which had a severe degree of focus breathing.

When shooting subjects with a shallow DOF, or at near distances, you may notice the background or foreground of your images changing in size as the lens focuses. This is known as focus breathing, and it’s caused by light entering different elements of the lens at different depths.

It’s most common when shooting at prime and wide-angle focal lengths, and whenever you shoot with a lens stopped down to apertures of f/4.0 or smaller. The overall image size appears to change as you change your focal distance, but the important thing to remember is that this will not affect the amount of sharpness in your final photos.

How To Deal With Focus Breathing In Film Production

This video is a complete guide on how to deal with focus breathing in film production. It discusses what it is and then focuses on ways to avoid it. 

These tips will help you achieve sharp footage. This is an excerpt from the upcoming “Digital Film Making: Cinematic Motion Design and Stabilization”, a course by Ben Morden at Lynda.com. 

In this video, I am going to show you how to deal with focus breathing in film production.

Essentially, what it means is that if you are focusing on a subject, then if the camera or the subject moves, then your level of perceived sharpness changes. The change can be slight, or sometimes quite dramatic and obvious.

If you’re new to the world of professional HD film production, the last problem that you want to deal with is focus breathing; a relatively common occurrence where a camera’s autofocus system misreads a subject’s distance and makes an adjustment, resulting in a soft image. 

While quite widely known among experienced film producers, focus breathing is an often overlooked issue that can have serious consequences for novice filmmakers.

In this last part, we will cover how to eliminate the problems with focus breathing in film production.

How To Eliminate Focus Breathing In Film Production

Focus breathing is a phenomenon that happens in filming. It is caused by the breathing of the person in focus or the camera operator, making the shot “breathe.” It can give great effects to film, but it can also cause unwanted movements in video clips during changes in focus.

So, how does it happen? When a zoom lens is used on a video shoot, it will pull air out of the room and when it is extended back to its proper shooting focus, that air rushes back into the room and can cause some light flicker, or even more noticeable side effects like seen in this article.

The term was once used for small movements in-between different scenes, but it is now used for any focus problem during filming.

As a director, I have had to deal with focus breathing on several occasions, so I have acquired some insights that I’ll share with you here. Finding the right solution will help you eliminate this effect and make your video projects more appealing and professional.

But first, get your copy of this eBook to learn how to eliminate focus breathing, and have a better film! Focus breathing may be an issue you have dealt with in the past, but it sure can be resolved.