SLRgear (Click here) tested the new 8mm fisheye PRO lens from Olympus:
Images shot with the lens offer pleasing sharpness; corners are often out of focus in wide-aperture (ƒ/1.8) shots because of the subject distance, rather than characteristics of the lens. It doesn’t take much to get the full frame of a scene in focus – just back up and stop down a few aperture stops.
Mirrorlessons (Click here) posted the full M.Zuiko 7-14mm comparison with the Panasonic 7-14:
There isn’t a drastic difference concerning sharpness. The differences in perspective distortion are a question of taste. I would say that the Olympus lens can be a better choice for precise architectural compositions while I could recommend the Lumix version for landscapes. The M.Zuiko version has the obvious advantage of having a faster aperture, which can make all the difference on a m4/3s camera, especially when shooting indoors. It is also more versatile thanks to its closer focusing and bokeh capabilities and has a better resistance to flare.
7-14mm f/2.8 PRO lens: Amazon, Adorama, BHphoto, GetOlympus, WexUK, AmazonUK, AmazonDE,
8mm f/1.8 PRO lens: Amazon, Adorama, BHphoto, GetOlympus, WexUK, AmazonUK, AmazonDE,
Titanium E-M5II: Amazon, Adorama, BHphoto, GetOlympus, WexUK.
7-14mm Olympus LC-79 Lens Cap at BHphoto.
Olympus PPO-EP02 Dome Port for 8mm at BHphoto.
Olympus PPZR-EP05 Focus Gear for 8mm at BHphoto.
Olympus POSR-EP10 UW Anti-Reflecting Ring for 8mm at BHphoto.