Documentation Guide to Using Filters to Their Maximum Neutral Density Filters (ND) What is a neutral density filter (ND)? How strong is my ND filter? What strength of ND filter should I use? How do I calculate the correct shutter speed using an ND filter? Minimising 'light leak'? Graduated Neutral Density Filters (GND) What is a graduated neutral density filter (GND)? How strong is my GND? What are the different types of GND and when should I use them? What strength of GND should I use? Tips for using your ND and GND filters effectively Circular Polarizing Filter (CPL) What is a circular polarizing filter (CPL)? How do I use a CPL effectively? Natural Night Filter What is the ‘Natural Night’ filter? How do I use the Natural Night filter effectively? View Details