The manufacturing quality is at the appointment: thin and light (aluminum construction), the ring slides well (360 °), the assembly of two rings and the filter is very good (no game).
Mounted on a Canon 15-85 IS USM + Canon 100D, I have not experienced particular problems with the loss of brightness due to this filter.
Be careful though! The filter is very thin, if you climb too hard, you'll struggle to unscrew it. If this happens, do not panic: take a flat lace, wrap well around the mounting ring and grab a pen (for example) you will use to twist the lace for tightening the ring. Thus, the force will be evenly distributed around the ring and you will not risk forcing the fold.
To avoid this mishap again, put a little soap or petroleum jelly to the threads.
