I used a B+W 10-stop ND filter on my a99 ZA 24-70 and recently picked up one for my A7R FE 24-70. I haven't done a ton of long exposure work in the past, but plan on doing more going forward. I've decided that I'm done with these screw-in filters. So, I'm thinking Lee Big Stopper, or similar type of arrangement. Anything you folks like that I should check out?