Samyang AF 18mm F2.8 FE

Testers find the centre good at f/2.8, with borders and corners improving markedly by f/5.6, which is the sweet spot. Field curvature is low, and lateral CA is small and easy to correct. Vignetting is the main optical weakness at well over 3 EV wide open, and distortion has a wavy pattern that profiles do not fully straighten, which matters for architecture.

Flare resistance and coma correction are better than the price suggests. The build feels plasticky and the AF settles slowly with small audible corrections, but reviewers still recommend it as a cheap, very portable ultra-wide, provided you buy a well-centred copy.

Owners pick it as a travel, hiking and gimbal lens because it almost disappears in a bag, and many pair it with Samyang's other Tiny primes. Taking regular screw-in filters at 18mm is a frequently cited plus.

Complaints focus on copy variation (decentred samples), dark corners, a slippery barrel that collects fingerprints, and weak, uneven sunstars from the 7-blade aperture. Some owners report AF hunting in low light.