How I used an ND filter to subdue the hustle and bustle of London at peak time

Long exposure of people walking along London's Millennium Bridge with St Paul's Cathedral in the background .

A bustling metropolis, such as London in the UK, provides a fascinating contrast of old and new, with modern glass-and-steel structures butting up against historic buildings. However, cities are also full of people, traffic, building work and other unsightly distractions that could spoil your shot.

But employing the use of an ND (neutral density) filter can help blur moving elements, turning a choppy river into a smooth surface and making moving boats magically disappear (as in the shot below).