Progrey Filter Holder & 10 stop ND Filter
I am not affiliated with this company, but just thought I would share my experience for others seeking a filter system for a Nikon 14-24mm or Canon 14mm lens. I considered purchasing a Lee SW150 system as my other standard filters are Lee however, after a bit of research, I heard that you could get some light leakage with the SW150. A friend had purchased a Progrey and spoke highly of the system so I thought I would give it a go. The filter holder has excellent build quality (it's metal, not plastic), no light leakage that I can see and, most importantly, I don't appear to get any colour cast with the 10 stop filter. On top of all that, the customer service I received was fantastic. In my opinion, an excellent system all round. Hope this is helpful to those researching a filter system for an ultra wide angle lens.