The 12mm f2.8 is designed to be small and light, and the optical design features 12 elements in 10 groups, an aperture range of f2.8 to f22, and an angle of view of 99° (when mounted on APS-C sized mirorless cameras). Weighing only 360g and measuring just 65.8mm from tip to mount, it should prove a good fit for all mirrorless systems.
The 8mm f3.5 fisheye lens features 11 elements in 8 groups and is just a little heavier than the 12mm at 440g. It has an aperture range of f3.5 to f22 and has a minimum focus distance of 10cm.
For more information, you can check out the official Meike website here.