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nd filter

Karizma Karizma 1 post

Hi, I have a canon 7d and currently only have 2 lenses. 50mm 1.4 and 15-85 mm 3.5. I want to get an nd filter and was about to purchase a variable one until I read about the issues with vignetting and colouration etc. Is this the case with all nd filters or just variable ones? I want to do use for time lapse photography and also video. Which would be the best for me? Ive researched a lot and still cant decide, so many brands etc. Money is not an issue, id rather have quality.

Peter Hill Peter Hill 595 posts

If you’d rather have quality, forget about variable NDs.

ND filters require very precise manufacturing to ensure consistency of density, and the “vari” concept just makes that task harder. Knowing that brings an expectation that such filters will be higher in price than your normal filters, such as CPs and UVs. Which means that, for me, the price of the Singh-Ray Vari ND, for example, did not justify the standard they had achieved. This also means my expectations for cheaper versions is a lot less. Marumi, for example, make a vari ND which they claim covers 1 to 9 stops. You get it from Amazon from $140. Why Amazon? Because the usual stockists, eg Adorama and B&H, do not stock it. Marumi also sell ND x400 equivalents for $20, and that tells me a lot about what to expect from the quality.

Whilst the actual variation in density from 1 to 9 may be achieved, it is the side effects which are the problem, and they become more pronounced as the density increases – banding and casting. So, if in practice the vari ND can only give problem-free results at no higher than 4 or 5 or 6 stops, their relative utility is significantly diminished. Hence, in theory, a sound suggestion for eg a trip requiring minimum gear haulage, but the results may be frustrating.

The markings on vari-NDs do not equate to densities and are only a guide, ie you never actually know what density you are shooting at. If you decide to get 2 (or more) straight NDs I would recommend getting slim versions, especially if you are going to put them on a wide angle lens like the 15-85mm, so that when you stack them on your lens you reduce the scope for vignetting (the circular edge of the last filter coming into frame).

If it were me I would get the ND x400 and a 3 or 4 stop, but that’s only because I use the ND x400 all the time with occasions of wishing I didn’t have to go so dark and wanting my 3 stop instead. In using the ND x400 as my default filter I am probably being lazy, but I am finding I can adjust my other settings accordingly, mainly exposure time. Indeed I routinely shoot with the ND x400 at speeds from 2 seconds up to 240 seconds, and sometimes much longer. I prefer not to have to adjust ISO and/or aperture just to suit the use of the ND x400 if I can. (The higher the ISO and the longer the exposure the more chance of dead pixels, oversaturation and casting on the fringes. By oversaturation I mean waterfalls becoming blue for example.)

I mention the ND x400 and not the B+W only because I experience less casting with the Hoya on really long exposures. Both are fine products, indeed the B+W seems to slide onto the lens much more easily than the Hoya. I think it’s more robust than the Hoya and l’m much less nervous getting the B+W off when stuck. I can’t remember off hand if either are in slim.