The Mamyia Sekor SX 2.8/28mm is well built and rather lightweight (205 g) wideangle lens with M42 mount. Focusing on my sample is rather stiff, ant the MFD is a common 0.3 m. The Sekor 2.8/28mm has a [7/7] construction with a positive-leading front group. It rubber focusing grip tends to rip, however this can be fixed by re-glueing it carefully to the lens barrel.

The lens performs surprisingly well, clearly outperforming the Zeiss CY 2.8/28mm (which never was considered as stellar lens): Corner resolution on 24 MP FF cameras is better at f2.8 and at f5.6. Only at f11 both the Zeiss and the Mamiya level out.