I've recently been looking at strong ND filters, and it had drawn my attention to their prices too! They are absurdly expensive! (Well, Lee Big stopper, B+W and some other brands are particularly the ones I looked at.) After reviewing Mr. Google, it seems like other brands would work just as well, even for screw-in filters. A few brands kept coming up, which are as below: Hoya, Bower, Tiffen, Haida, NiSi, Camdiox and others. Have anyone tried these cheaper brands? And are there any difference?