Today’s Question: I regularly watch your Venice video [“Composing Photos in Venice”]. I find it very informative and just love it. Could you tell me which neutral density filter that you use most commonly? I am torn between purchasing the 6-stop versus the 10-stop at this point. Do you find that the 6-stop is more versatile?
Tim’s Quick Answer: If I could only choose one neutral density (ND) filter, it would be the 10-stop version. This provides more creative options in terms of very long exposure times, including the ability to create relatively long exposures in daylight conditions. Also, you can always use the camera’s ISO setting to achieve a faster shutter speed if necessary.
More Detail: In most cases I carry both a 6-stop and a 10-stop ND filter. Between the two, I tend to use the 10-stop version more often. Quite simply, in situations where I want to create a long exposure, the ability to create a longer exposure time is usually advantageous. In other words, if a 6-stop filter will produce a good result, the 10-stop filter will often produce a better creative result.
Of course, a longer exposure doesn’t always produce a better creative result. It is most certainly possible for an exposure to be too long, causing moving objects to completely disappear rather than simply being blurred, for example. And, of course, a long exposure will result in increased noise in the capture as well.
Ideally, I prefer to use an ND filter with a strength that is best suited to the specific photographic situation. But that also requires purchasing and carrying multiple ND filters. If you prefer to carry a single filter, I would personally choose the strongest ND filter you think you’re likely to use.
You can then increase the ISO setting for situations where you need to achieve a faster shutter speed. For example, let’s assume you have a 10-stop ND filter, but you want the effect of a 6-stop ND filter. You can simply raise your ISO setting by four stops to achieve this result. Keep in mind, however, that increasing your ISO setting by four stops means going from (for example) 100 ISO to 1600 ISO, which could potentially lead to significant noise depending on your specific camera model.
The key is to choose an ND filter (or multiple filters) based on your own anticipated usage.