All levels of photographers and videographers are affected by focus breathing. It may be a simple breathing exercise, but it impacts all camera users. Even though it is a prevalent condition, few people know it.
We’re here to help if you’re unsure what concentration breathing is. We’ll examine what focus breathing is and why it occurs. We’ll see what we can do about that.
The term “focus breathing” refers to the tiny shift in focal length when a lens’ focus is altered from infinity to MFD or vice versa. You look through your camera’s viewfinder and rotate the lens’ focus ring from one end to the other. The lens appears to zoom in or out very slightly. Focus breathing refers to this shift.
Focus breathing does not affect still photography. It doesn’t matter if the lens is a prime or zoom. Even the most costly professional-grade lenses display focus breathing even if you’re shooting in servo focus mode. The slight focal length shift as you track an approaching target. It makes such little difference in the framing of your image that it’s almost unnoticeable.
Focus Breathing Defined
Your camera lens has a focus ring, whether it’s for an SLR, DSLR, or mirrorless camera. Rotate that ring to fine-tune the focus of your lens until the image in the viewfinder is clear. Then take a picture. The focus ring on various lenses can vary the angle and magnification of your subject, depending on whether anything is in focus. It may appear closer or farther away. The variation in clear focal length is known as focus breathing or lens breathing.
The image seen via the viewfinder appears to be “breathing” when this occurs, hence the term. Focus breathing can occur with a zoom lens or a prime lens (a lens with a fixed focal length, such as 50mm). It always results in an apparent decrease in focus length rather than an increase. In other words, it will appear as if you are looking at things from a slightly different perspective. For a demonstration, watch a movie produced by HDSLR35 Online Filmschool.
In other words, even if your lens is a constant length, it will appear to zoom in and out when you alter focus. This difference is so slight in most lenses that it does not affect the final image. Especially since it only occurs at close focusing distances. Some lenses focus on breathing concerns, making them difficult to use.
Unless photographers try to put together many photographs at different focal points for a more detailed shot, they won’t notice the lens breathing much (a technique called focus stacking). When the focus shifts, the frame zooms. Distracting the viewer, taking them out of the narrative you’re trying to construct.
Why Lenses “Breathe”
Camera lenses use several glass lenses. Lens elements, or “elements,” are made up of these glass fragments. This design makes focusing a lens easier, faster, and quieter. Mainly if the lens contains an autofocus motor, it also implies that the focusing mechanism for your lens is completely contained within the lens barrel.
The exterior half of the lens will not move when you alter focus unless you’re using a zoom lens. Rather, some of the internal glass elements move while others stay put. The lens breathing effect is caused by the change in the distance when the movement occurs.
Today’s lenses can mostly correct this. You’ll notice little focus breathing on many newer models compared to older models.
How to Check for Focus Breathing in a Lens
If you have the lens you’re about to buy in front of you, you can check for excessive focus breathing. Mount the lens to your camera, set it on a tripod, and adjust the focus ring from close to infinity. A small amount of zooming in and out as you change focus is typical. If you notice many zooming in and out as you change focus, you might want to try a different lens.
Look for the “maximum magnification” number in the specs if you look at them online. It’s also known as the “reproduction ratio” or “highest reproduction ratio.” The greater this number, the less focus breathing the lens will have.
Modern lenses feature built-in focus breathing correction. Once you’ve figured out how to compensate for it, you won’t notice it.
Photography Life for a more in-depth and technical look into focus breathing, if you like to be more visual, this three-minute video from DPReview TV also does an excellent job of presenting the subject.
Every photographer encounters the issue of focus breathing. It isn't a problem for the majority of people. It's not uncommon for concentrated breathing to go unnoticed. The cinematographers and photographers that use focus stacking may have issues.
To reduce the effect, extension tubes might be employed. There is a price to pay. Avoiding lenses with a history of focus breathing is the best solution. For video producers, cine lenses are the greatest option.