Made in Germany by Schneider Optics, considered by many to be the premier maker of photographic lens-mounted filters, the B+W ND F-Pro with MRC is the reigning king-of-the-hill for screw-in type neutral density filters.
B+W's filters are made with world renowned "water-white" Schott glass for pure light transmission, inasmuch as the best glass allows. F-Pro denotes the use of B+W's signature front-threaded brass rings, and with this metal you can be assured they will play nice with other filters should you decide to stack them. Few things are as aggravating as monkeying with a stuck filter when you're out in the field as brass rings helps prevent your filters from getting stuck together. The F-Pro spec also means the filter bezel is shallow enough to allow you to mount this filter on a wide-angle lens. In fact, you should be able to get away with a 24mm focal length on a full-frame camera before you see filter vignetting (the darkening of the corners from the filter rings starting to come into view of the frame) with this filter.
B+W's best filters are multi-resistant coated (MRC). These coatings reduce lens flare considerably, are extremely hard which guards against scratches, and make cleaning smudges from the glass easier. The MRC process also creates a surface that is "hydophobic," meaning that water beads and rolls off the surface. Most importantly, the B+W ND F-Pro MRC has no noticeable color cast. This means that when you use it, you won’t have to spend extra time post-processing the images to remove unwanted color shifts. This not not only saves you time but also prevents the accompanying aggravation as well!
The model listed here is the 2-stop variant, as 2-stops of light reduction might be the single most popular density among portrait and landscape photographers. Two-stops of neutral density will allow you to isolate subjects using a wide aperture for shallow depth-of-field on sunny days and it will open up some artistic possibilities like blurring moving water or perhaps capture the swaying of tall grass in an open pasture. The B+W ND .6 F-Pro with MRC neutral density filter will let you do all that with the best over-all quality on the market.
Singh-Ray 77mm George Lepp 2-Stop Thin Neutral Density Filter
Based in Florida, Singh-Ray has long been a provider of top quality photographic filters. In fact, they’re the pioneers that brought graduated neutral density filters to market that are now so popular among landscape photographers. The George Lepp 2-Stop Thin neutral density filter offers many of the performance features of Singh-Ray's very expensive slide-in square filters, but in a more manageable screw-on form-factor. This manufacturer’s neutral density performance is legendary and this filter delivers on that reputation.
Singh-Ray's George Lepp Thin neutral density filters use a brass ring to help prevent jamming, but do not have front threads for stacking other filters in front of it. By eliminating the front threads Singh-Ray claims you can achieve a wider field of view before vignetting. You can still stack, just be aware that this filter will only work on the top-most of the stack. This is generally never a problem for solid neutral density filters as they are most conveniently added last on the stack anyway.
This filter is not made of glass, but instead manufactured from optical resin. This is the same material prescription glasses are made of, so expect it to scratch in the same manner. Also, the George Lepp neutral density filters are not coated against flair. This is important since shooting with a bright light source somewhere in the frame may cause this filter to flair significantly more than its multi-coated competitors. It is Singh-Ray's philosophy to not add anything to the optical path that is not absolutely critical, and they are of the opinion that coatings are not critical. What you do get is one of the most copied neutral density formulas on the market.
Hoya 77mm Pro 1 Digital Neutral Density 64x Filter
Based in Japan, Hoya is a very popular name brand for photographic filters and they offer many quality products including the ND Pro 1 Digital Multi-Coated neutral density filter. The Pro 1 line is Hoya's top of the line and with this list of features, it's easy to see why. The ND Pro 1 Digital Multi-Coated neutral density filter offers several coatings to dramatically cut down flaring and aid in filter maintenance. This Pro 1 Digital is ultra thin, but retains front threads for stacking.
By being ultra thin, this filter allows you to use even wider than normal lenses without vignetting. Hoya has even gone to great lengths to reduce unwanted reflections by coating the inside of the filter ring with a matte black finish. The rings, however, are made of anodized aluminum which may cause galling against your lens if screwed on tightly. With a little care you may never have to worry about this filter getting stuck, but if it does it would be helpful to have a filter wrench in your bag. Filter wrenches are cheap and come in pairs in case you lose one.
As you might expect, the Hoya ND Pro 1 Digital does not introduce color casting into the image. Hoya's glass is not Schott, like the other glass filters in this list, but instead made from Hoya's own in-house glass making facility and the results are stellar.
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.
B+W 77mm ND .6 F-Pro SC Neutral Density Filter
If excellent light filtering performance is just as important to you as not filtering all the money out of your wallet, the B+W ND .6 F-Pro SC neutral density filter is for you. The SC variant of B+W's neutral density filters offer many of the advantages of the more expensive MRC version at about half the cost. If money is an object, but you still demand top-on-the-line filtration, the B+W ND .6 F-Pro neutral density filter is for you.
You still get B+W's excellent neutral density performance which means no color casting despite the lower price point. Since this filter is in the F-Pro line it comes with front-threaded brass rings, just like the MRC version. And, as the "SC" denotes, this filter's glass is only single-coated on each side to help reduce flair and make it easier to clean, however you might find that it does not perform as well as the MRC variety where flare is concerned. Most budget filters don't have even a single coating, much less coat both sides.