I am more familiar with Nikkor lenses, this right is not really comparable on many points, but at that price, if you do not pro photo, if like me for fun, memories, poster Internet is really enough!
A light game development ring (which seems almost pointless way), not by rotating but, moving back and forth. Not annoying at all ...
The dive, not as good as on my Nikkor 1.8; 35mm (Normal at this price, to be expected.)
I had no confidence to the fisheye adapter that is mounted on goal nor the means to take a Nikkor or Sigma, I must say that this goal is a good compromise.
I do not regret!
Photo 1 = fisheye; photo 2 = 35mm space without moving ...