Many filter manufacturers make several grades of filters to offer them at different prices.
B+W makes less expensive, uncoated, aluminum framed filters... single coated filters that cost a little more... and multi-coated, brass framed that are more expensive... plus in some types "nano" multi-coated that are their top-of-the-line, more resistant to scratching, easier to clean and most expensive.
Hoya does something similar.
You might not see as many choices in ND type filters as you do in, say, Circular Polarizers. But you will probably at least find uncoated and coated in many brands. Regardless of brand I'd definitely look for multi-coated. Hoya labels their multi-coated "HMC" and B+W labels theirs "MRC".
Brass frames are less likely to bind and get stuck on lenses that have aluminum or other types of metal threads... but may not be necessary on modern lenses that use plastic threads instead.
If you are seeking specific ND strengths, you might need to consider multiple brands. Most brands make only certain types of ND.
For example, B+W offers:
ND.3 (101) = 1 stop
ND.6 (102) = 2 stop
ND.9 (103) = 3 stop
ND1.8 (106) = 6 stop
ND3.0 (110) = 10 stop
And Hoya offers:
ND1000 = 10 stop (multi-coated?)
NDX500 = 9 stop
NDX200 = 7.6 stop
NDX100 = 6.6 stop
NDX64 = 6 stop
ND32 = 5 stop (multi-coated?)
ND16 = 4 stop (multi-coated?)
NDX8 = 3 stop
NDX4 = 2 stop
NDX2 = 1 stop
Haida offers uncoated, multi-coated and nano-multi-coated:
ND0.3 (2x), 1 stop
ND0.6 (4x), 2 stops
ND0.9 (8x), 3 stops
ND1.8 (64x), 6 stops
ND2.7 (400x), 9 stops
ND3.0 (1000x), 10 stops
I'd be concerned that testing of UV filters might not be very applicable to choosing ND, CPL or any other type of filters (Lenstip site has a CPL comparison, but it's a big fail because of some issues they never went back and corrected). Also, a seven year old "test" may or may not be relevant today. In some cases, newer types of multi-coatings are now offered and manufacturers have changed their designations.
sidpearce wrote:
The very best filters are Lee.
Problem is they are made of quality glass and you handle with care
Lee filters are excellent. Their 15 stop Super Stopper is one of the strongest ND made by anyone. But the problem is that they only make square (100x100mm & 150x150mm) and rectangular type which are expensive, bulkier and difficult to shade with a hood than a screw-in filter... plus Lee are not multi-coated.
Weird name! "Breakthrough" sound to be very good, but their "X3" are also VERY expensive (and I haven't been able to tell what the difference is between those and the cheaper "X2" ). Only available in three strengths, too: 3 stop, 6 stop and 10 stop.
The Digital Picture appears to be a more recent testing and comparison, since it includes the relatively recently inroduced Breakthrough. It also includes Heliopan and Singh-Ray, two more excellent, if pricey, brands. This test only looks at 10-stop filters... so it omits some Hoya that might be multi-coated and perform better than the 10-stop sample Bryan tested.