One of the challenges associated with ultra-wide angle photography is the need to have both filters and a filter holder sufficiently wide and narrow not to cause vignetting when using the wider lenses.
My favourite lens has been the Nikon 14-24mm f2.8 lens - amazingly versatile and delivers fantastic detail. As we now expand our horizons to take up medium format as well as 35mm, we also have to be able to cope with the Schneider Kreuznach 28mm f4.5 (17mm 35mm format equivalent) and the Schneider Kreuznach 40-80mm f4.0-5.6 (25-50mm 35mm format equivalent). The 28mm has an aspherical front element like the Nikon and the 40-80mm has a 105mm front element. Both presented some challenges!
After trying the Wonderpana filter kit for the Nikon 14-24mm lens, we found that the higher rated ND filters that we could get (Wonderpana has a limited range at the lower ND/graduated end) - from Formatt Hitech - were a bit narrow for the slots in the Wonderpana holder. This meant we needed to find something that would have the same capacity to deal with ultra-wide lenses, but also cope better with a 'standard' 2mm thick 165mm filter.
Enter the amazing Lucroit filter holder and adaptors! (lucroit.com) Not only do Lucroit have an adaptor for most of the difficult lenses (Nikon 14-24mm and Schneider 28mm aspherical), but when we contacted them to ask whether they could custom-make an adaptor ring for the 40-80mm Schneider, they agreed straight away!
I've seen a couple of blogs say they think the Lucroit holder is 'poor quality' because it is made from plastic, but I doubt whether they've used one! The beauty of the adaptor-ring/filter holder combo made from this very tough, but flexible plastic, is that it is the most stable mounting system we've yet found. All we need to do is lodge an adaptor ring on the front of our main lenses and then the filter holder simply clips off one and onto the next in a matter of seconds.
But the story gets better.. After agreeing to custom-make a 105-105mm adaptor for us - at the same price as their other adaptor rings - Lucroit then got back to us and said that they recommended a 105-112mm ring - which they could guarantee would not vignette. We agreed and within 24 hours, they had made a prototype, tested it and found that there was some light entry from behind the adaptor ring and made another prototype modifying the actual filter holder - and sent us a movie of it in action!
So we now get to use our Formatt Hitech filters with every lens in the collection - both 35mm and medium format - and don't have to carry two or more sets of filters and adaptors when we're in the field. I am still astounded by the great service and super-swift response we have received from Lucroit - especially given that we are not well-known or a major customer - just photographers trying to do what we do!
Needless to say, Lucroit have a customer for life!