Heliopan 77mm ND .6 ES Neutral Density Filter
Though more popular in Europe, Heliopan has many fans stateside that swear by their products, as well. Heliopan is a German company known for expensive, high-quality products and their filter line is certainly no different. The Heliopan ND ES neutral density filter has all the hallmarks of a great filter, including the price.
Heliopan ND ES filters are made with front-threaded brass rings to prevent sticking with other filters and allow for easy stacking. They are made from dual-sided single-coated, optically pure Schott glass and perform exceptionally well where color casting is concerned. Since it's not multi-coated, like the B+W MRC or the Hoya Pro 1 Digital, you can expect the Heliopan to suffer a little bit more from flaring, but it should still outperform the Singh-Ray in this regard. However, like the B+W, Hoya, and Singh-Ray products, the Heliopan handles neutral density filtration flawlessly, by not adding a color cast nor degrading the sharpness of the image.