You are the first person to put your lens on your camera.
The factory set up your camera and each of your lenses separately. Nobody has tuned them together, and small differences between the two add up: a shot that should be crisp comes back a little soft.
On a DSLR, autofocus is measured with a separate sensor, not the one that takes the picture, so this matters most. Mirrorless cameras focus with the image sensor itself, and those with an adjustment still need calibrating: on Nikon Z cameras, 1 in 6 native lenses is noticeably out, and 46% of F-mount lenses on the FTZ adapter. Any lens on an adapter, such as a Canon EF lens on a Z camera, adds another joint to the light path. Read how it goes wrong in the illustrated guides to DSLR and mirrorless autofocus.
Why calibrate?How many lenses need it?
85.7%
of lenses on the D850 would improve noticeably with FoCal calibration, and 67% significantly.
Source: FoCal IQ: D850 (F mount), from 16,645 results uploaded by FoCal users.
76.8%
of lenses on the EOS 5D Mark IV would improve noticeably with FoCal calibration, and 49.7% significantly.
Source: FoCal IQ: EOS 5D Mark IV (EF mount), from 28,397 results uploaded by FoCal users.


