So I am looking to add a bit of punch in my landscape shots. I need a recommended circular polarizer (i did try a search). Also, I need an ND-Grad filter recommendation- including the right "holder" for it (Cokin P is all I know about). For polarizers, I know there is a large variety of brands and qualities, so the prices must get steep quickly. I also don't have $100 for a CPL. The size I am looking for is 58mm for my Mamiya Sekor-C lenses, and I will buy stopdown rings for my 52mm Nikkors. Thanks for any info.