This dual aperture series at 14mm shows the severe loss of resolution that occurs due to the focus shift of the Nikon 14-24mm f/2.8G ED. Shot with the Nikon D810, this behavior is even more damaging on a Nikon D850.
While the 14-24 is a very sharp lens wide open, its performance declines with stopping down, with an obvious loss of sharpness at f/4. And it never recovers the sharpness of f/2.8, even at f/9, due to its pronounced rearward focus shift.
Includes images up to full camera resolution, and crops.
Roland VB writes:
Sometime ago you stated that Nikon D810 now automatically corrects for focus shift.
I still own a D800 so I’m not able to investigate myself.
What’s the reality here and are corrections also applied to non Nikon lenses like Sigma?
DIGLLOYD: my tests for correction of focus shift by the Nikon D810 showed that the D810 did indeed appear to compensate for focus shift, which AFAIK applies only to conventional autofocus system (phase detect AF, e.g., through the viewfinder).
On my to-do list is to verify that the D810 corrects focus shift with the 14-24 as per above and whether the D850 does the same. In general, conventional AF cannot be relied upon for assessing lenses, which is why I never use it for lens assessments and why I deem any tests that does so a junk test—unless the goal is to test that conventional AF system + lens combination—but it is not a valid lens testing protocol.
As for Sigma, most of the Sigma DG HSM Art lenses show no focus shift, the Sigma 12-24mm DG HSM Art having pronounced focus shift and thus a notable exception.