I'm off to New Zealand in early January so have asked my son to buy me a set of Cokin GND filters and holder etc for my birthday in December. I came back from a trip to China this year with so many blown out skies which was really disappointing and unfortunately when travelling you can't always shoot at the best time of day. Are these filters really hard to get used to and if so anyone have any useful tips as I'll only have a couple of weeks to practice with them before we go.