I've had a great Nikon AF 16mm f/2.8 Fisheye for over a decade but this lens doesn't become automatic with the new lens Nikon Z series cameras focus with a Nikon FTZ adapter. So I replaced it with this fisheye lens, which auto-focuses with an FTZ adapter and is also optically a more flexible lens. The only downside to the upgrade is that you lose about a stop at maximum aperture.
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