So I bought a set of (pretty cheap) ND filters a couple of years ago and took them on holiday to Canada with me last year. I managed to get a couple of OK shots but most of them looked something like this (ignore the other general crappy attributes of this photo):
All the colour is washed out and there's almost no detail left which sort of ruined most of the opportunities I had to take some nice waterfall long expos in one of the best places to do so (sadface).
Since then I haven't really bothered using them as I just decided they were useless but I'm looking into long exposures using ND filters again and before I go wasting loads of money on a fancy new set, I'd just like to confirm whether this is just something I'm doing wrong or it's something that can be corrected in post (I've tried adjusting the temperature and tint but it doesn't help the washed out nature of the exposure).
Maybe it is just crappy filters? If so, does anyone have any recommendations for a good set that isn't going to cost me hundreds. Ideally I'd like another set of square filters so I don't need a new set for different thread sizes.