This pendant!
Well actually it expanded viewing angle of its kind between 12 to 14mm instead of 18.
But big image distortion on the sides and center! Pique, loss of image quality, blur on the bort during a shooting of a landscape and see the edges as it is 18mm ..!
For the price, this is correct but for that price you should not expect miracles: /
Tested by photographer Lafeuille