A 8-16mm lens APS-C is equivalent to 12-24mm in 24x36. The viewing angle of this goal is simply gargantuan. This is a very entertaining toy that allows amazing effects. However there still has some downsides: - The front lens, very prominent, is fragile. Do not leave it lying anywhere - Distortion, clear, appears to 8mm, which is not corrected by the housing ("thank you" Nikon!) - This goal may lack a little sharpness, but 8mm do not be too hard! For comparison, images taken with a fisheye 8mm Ukrainian construction gives clearly less stitched pictures. - The focus is clearly audible engine for video jacks - No simple possibility of adapting filters on that goal! The solution of using the cap proposed by the manufacturer is ridiculous.