Some Tips and Skills of using the Filters. Thanks for PhotographyTalk provide us the articles~
How to use the GND filter to make your picture better.
In use I found the Haida filters did not introduce any strong colour casts, drop of image quality or purple fringing. They are extremely easy to keep clean with just a lens cloth or with bit of fresh water and cloth to remove salt spray or stickiness from
Over the past couple of months I have been using Haida's 150mm filter system, these optical glass filters are perfect for use with ultra wide-angle lenses.