Buying an ND filter


I’ve always liked to capture motion in my photos. Like the motion of people in my Vatican museum spiral staircase photo, or long exposure of waterfall, I like them all.

Vatican spiral staircase Rapids IIb

There’s something special about capturing perceived movement in still images — a sense of dynamism.

Now to achieve the blur associated with the motion, I need a slow shutter speed, which means that either natural light is low and hence less light is getting to the sensors, or I artificially limit the amount of light getting through. There’s not much I can do with the former, but I can control the latter.

One way to limit light is with the use of a neutral density (ND) filter. I already have a circular polarizer in my arsenal, which can act as an ND filter as well since it limits light transmission due to the way it works. On checking, I found that it’s cutting the light by 1.7 stops. That means that if I normally shoot at a shutter speed of 1/100s, with the polarizer, the speed increases to about 1/30s or so. Not bad, but still not slow enough for a variety of subjects. So to get even slower speeds, I need an ND filter.

If I could swing it, I’d get a Vario-ND filter by Singh-Ray. But at about $350 for a 77mm filter, I don’t think so! There are instructions online to build it yourself with a circular and a linear polarizer, but that’s not what I want to do. To give myself the widest range of light reduction, I’m thinking of an ND filter that reduces light transmission by 4 stops. So basically, between my polarizer and the ND filter, I’ll have 1.7 stops, 4 stops, or 5.7 stops (if I stack the filters) reduction in light. With the filters stacked, that 1/100s can be increased to about a 1/2s exposure. This will come in handy with beach and wave shots when I visit Newport, Oregon shortly.

Currently, I’m looking at the Tiffen High Transmission ND 1.2 filter, which gives the 4 stop light reduction I’m seeking.

If there are some other filters I should consider, or if there’s a better way to do this, drop me a note.

Happy Friday, folks!


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