Nikon Nikkor Z MC 105mm f/2.8 S VR Macro Aperture Series: Focus Breathing
re: focus breathing
Many lenses have focus breathing, a change in focal length as the focus distance changes. This is a bad thing for video usage, far from ideal for focus stacking, and is the way to "cheat" on macro photography for a faster aperture—a 100mm might be a 60mm by the time it is at 1:1 magnification.
Nikon Nikkor Z MC 105mm f/2.8 S VR Macro Aperture Series: Focus Breathing
Includes a 9-frame series showing the changing in field of view.