To be honest, I did not find much difference using hoya pro 1 comparing to any other brands.
Just a protective filters and the names sound great pro. Otherwise it is just something to protect front elements of the lens.
The Hoya Pro 1 might have decreased the amount of purple fringeing for my A* 200mm macro. There supposed to be some fringeing problem with this lens but I notice little problem of CA. Maybe this is due to the credit of Hoya Pro 1
