Even if you don’t know the definition for lens breathing, everyone can probably identify it when it happens, once they do.
Lens breathing refers to the shifting of angle of view of a lens when changing the focus over time. Higher end lenses try to minimize this effect, but recreating this effect in your work can make for a more beautiful focal change.
Djordje Ilic’s last project “Legend 964” uses this effect heavily. Although lens breathing can be recreated in 3D, it is much more practical to reproduce it in the composite stage.
Djordje walks us through how to do this with The Foundry’s Nuke, but the effect can just as easily be done in After Effects, or any other compositor just the same. It’s silly a matter of manually zooming the image while the focal change is happening. Simple yet effective!