finally we have solution for 150mm square filter system for 150mm system which support Canon 14mm F2.8, TSE17mm, Nikon 14-24 F2.8, Tamron 15-30 F2.8, SAMYANG 14mm F2.8, SIGMA 12-24mm etc. and some test results from same filter manufacturer but it is on 100mm system [84dot5 RGND 100mm] . sample of RGND update 2016 March 4 … Continue reading Reverse GND for 150mm Square filter system