This particular lens sports a Canon EF mount. The aperture on the lens ranges from ƒ/16 to ƒ/1.4.
From Photospecialist
Zeiss Otus 28mm F1.4 ZE Canon
Clifton Cameras
Zeiss Otus F1.4 28mm Lens ZE Canon EF Fit
WEX Photo Video
Zeiss 28mm f1.4 Otus Lens - Canon EF Mount