Use an ND filter for longer exposures
If you’ve ever tried long exposure photography in broad daylight, you’ll know that even with the narrowest aperture and lowest ISO, it’s impossible to achieve very slow shutter speeds. To get around this problem, you can attach an ND filter, which blocks out a proportion of the light entering the lens without causing any colour tints. NDs come in a variety of strengths, but we recommend a 10-stop for this technique, which blocks out 999/1000ths of the available light, giving shutter speeds of several seconds even on bright days. Most 10-stop NDs, often termed Big Stoppers, screw onto the end of your lens, and only cost a few pounds. Make sure you buy one with the same thread size as your lens. Once the filter is attached, you won’t be able to see through the viewfinder, so you’ll need to compose and focus your shot first.
Above A 10-stop ND screws onto your lens, giving you much longer shutter speeds. This table gives correct exposure times when the filter is attached.