Considering a Variable ND Filter


Today’s Question: Are the variable neutral density filters worth the money?

Tim’s Quick Answer: While variable neutral density (ND) filters are convenient, I personally prefer to work with solid ND filters.

More Detail: One of the key benefits of a variable ND filter is that it provides the range of multiple solid ND filters in a single filter. For example, the variable ND filter I prefer ( makes it possible to reduce the amount of light reaching the image sensor in a range from about three stops up to eight stops.

In other words, with a single variable ND filter you have the same range of options as you might otherwise achieve with three or more solid ND filters. That is obviously a potentially significant benefit, both in terms of not having to carry multiple filters and being able to achieve a specific exposure setting more quickly since you wouldn’t need to change filters.

However, I generally prefer to work with solid neutral density filters. One of the key reasons is that a single filter has a single density value that you can adjust for dependably. For example, a six-stop solid ND filter involves adjusting the existing exposure by six stops when you add the filter.

With a variable ND filter you never really know precisely how much light you’re blocking, and therefore how much you need to adjust your exposure settings. You can often use the exposure simulation feature (or even metering) for your camera to set your exposure, but this often isn’t accurate especially at high density settings.

To be sure, variable ND filters offer a degree of convenience. However, I find that it is easier to simply have individual solid ND filters with predictable behavior. In addition, it is easy to adjust the ISO setting to refine the overall exposure setting, providing a similar (though admittedly not identical) capability compared to variable ND filters.

If you are interested in a variable ND filter, one that I highly recommend is the Singh-Ray Vari-ND filter. You can find the 77mm version of this filter here: