What is Focus Breathing in a Camera Lens?

When discussing features and specifications of a camera lens, focus breathing is a term often used. This issue can affect any lens, but it can also negatively impact your videography and photography. We will be discussing what focus breathing is and how to avoid it in this article.

Table of Contents

  • What is Focus Breathing?
  • An example of Focus Breathing.
  • Why does Focus Breathing Work?
  • Problems caused by Focus Breathing
  • Avoid the Focus Breathing Issue
  • What should you do about Focus Breathing?

What is Focus Breathing?

Let’s start by asking what focus breathing is. It is also known as “lens breathing” and refers to lenses and the way they magnify images at different distances.

Focus breathing is when the focal length of a lens changes in proportion to its focusing distance.

This behavior is present in both prime and zoom lenses to different degrees. This behavior can be seen by framing a scene, changing the focus from minimum to infinite and paying attention to the edges. You may notice that the shot appears to “zoom in” as the focal distance changes.

It is possible to take two photos and keep everything the same. You just need the subject in focus at zero in one and the minimum focusing distance in the other. You will notice that there is a slight difference in the focal length (magnification) even though they were shot while keeping the focal length on the lens the same.

Focus breathing is exaggerated because it increases with distance between two subjects (i.e. The distance between the two focused subjects (i.e., the photos) increases in focusing distance. The magnification as well as the angle of the view changes, which causes an apparent change in the focal length.

An example of Focus Breathing.

The two examples below show that the focus has been changed from the mobile holder to the mirror holder. As a result, the second photo appears to have been magnified, and slightly cropped in (they weren’t cropped in postproduction).

A photo with a close focusing distance.
Without moving the camera or adjusting the focal length, the focus is adjusted to a further plane. Notice how the composition has slightly changed a the edges of the frame due to focus breathing.

This GIF shows the photos alternated back and forth. Notice how magnification and angle slightly change when focus is changed.

Why does Focus Breathing Work?

Modern camera lenses often have an internal focus system, which allows for focus breathing. These lenses have an internal focusing system that allows us to change the focus manually or automatically. The front of the lens and barrel do not rotate or move, so only the smaller elements within the lens barrel can move.

This internal focus system offers many benefits including portability (smaller, lighter designs), faster focus (due the smaller set of focus element), compatibility (due front lens element not rotating during focus), constant lens length (the front elements do not extend during focus, especially useful in macro photography).

Focus breathing is the trade-off. The focal length of the lens will change slightly if you focus on the internal focus lenses.

There is a delicate balance between the optical quality and how quiet it is. It all comes down to the design and build of the lens, which is also reflected by the price. Cinema lenses have the lowest amount of focus breathing, or almost none, but they are much more expensive than a photography lens that is primarily designed for still images.

Problems caused by Focus Breathing

Cinema lenses must eliminate focus breathing because this phenomenon can distract from the video and is easily visible. Also, you will notice that lenses with the same aperture and zoom range may be labeled as non-cinema lenses and that focus breathing is one feature that distinguishes them (among other things).

Focus breathing can affect still photos in certain situations. This is especially true when you focus stack images with lenses that have a lot of focus breathing. To focus stack images, a photographer might take multiple images that vary in focus (MFD) from the background to the foreground. The stacked images will have a different focal distance and magnification, which can cause problems in post-production.

Photoshop versions older than 7.0 can handle minor changes in image stacking. You will need to crop the final image stacked even though it was shot on a tripod.

Avoid the Focus Breathing Issue

How can you eliminate focus breathing from photos or reduce it? It’s easy to either upgrade to or purchase a lens that doesn’t exhibit focus breathing. This is because it’s a feature of the lens, not how you use it. You can reduce it by using your current lens in certain ways.

Focus breathing can be most noticeable in photos that are taken at extreme focal distances. One photo focuses at infinity, the other focuses on the minimum distance. You might reduce this distance to take photos where the subjects are almost at the same distance from your lens. This will allow you to not need to adjust (or minimize) the change in focus between shots.

Many lenses made for photography, even higher-end lenses, don’t clearly state whether the lens has focus breathing. This makes it difficult to compare lenses side-by-side if this is an important issue for your photography work. You can compare the maximum magnification factor of a lens, or combination of lenses, if the magnitude of focus breathing is not listed. This is usually denoted as 0.15x (0.25x), 0.38x (0.71x), 0.71x (e.g. The lens will experience less focus breathing if the magnification factor is higher.

Another way to test for focus breathing issues with two lenses is to take real-world photos of it (on tripod) and then magnify the images. Two photos should be taken of an object that is within the minimum focal distance of the lens. The other one should be taken at infinity. Repeat this process for the other lens. If the phenomenon is present, it can be clearly seen at the edges.

What should you do about Focus Breathing?

Here is the final question. The final question is whether or not you should pay attention to focus breathing, and to what degree. Focus breathing is a key factor in lens selections if you plan to shoot videos. If the focus changes within the same scene, it will be obvious in a video. Modern video editing software can help, but they can cause the video to be jittery or unprofessional.

Focus breathing won’t make any difference if the lens is used primarily to take still photos. However, it might be useful in situations such as focus stacking and photos that are used in scientific studies. It is very difficult to tell the difference between photos taken with high focus breathing lenses and shots that have large distances between subjects.

Photographers often recompose photos as they move their focus. This allows the final composition to be exactly what they intended to capture.

Focus breathing is not something that should matter to you unless your primary interest is video. However, you’ll now be able to see why images taken with the same camera and the same settings might look different.