What to look for…
Wide viewing angles are often accompanied by wide-ranging features
The Samyang 14mm and Sigma 20mm lenses have built-in hoods and therefore no filter attachment thread. All other lenses are supplied with a bayonet-fit, petal-shaped hood.
All lenses on test have internal focusing, so the front element neither extends nor rotates, and all but two (the Samyang 14mm and the Sigma 20mm) have a filter attachment thread. Auto/manual focus The Nikon and Sigma lenses on test have ring-type ultrasonic autofocus, which is fast and whisper-quiet, with full-time manual override. The Irix, Samyang and Zeiss lenses are purely manual focus.
The Samyang and Sigma lenses have no weather seals, the Nikon lenses have a rubber seal on the mounting plate, and the Irix and Zeiss lenses have full weather seals.