1 Set up
Choose a location where there’s a steady ebb and flow of people passing by the camera. Obviously try not to stand directly in anyone’s way, but having said that, the centre of a busy walkway is ironically ideal as people will (generally) filter left and right of you. Here, I’m at one end of the Millennium Bridge in London looking back towards St. Paul’s Cathedral, clear of the foot traffic. As we’re going to be shooting a long exposure, a tripod is a must.
2 Refine your shutter speed
Select shutter-priority mode and your lowest ISO rating. Pick an exposure time of around 1/2sec to one second long: you want to blur the motion of the crowd, but keep it recognisable as people rather than abstract blurs of colour. If it’s a bright day then you may find that your aperture flashes at its minimum, and the image is overexposed. Narrow apertures are generally best avoided as softening and diffraction can become an issue.
3 Add filtration
If this is the case, then filters can be used to bring down the exposure, allowing you to use a mid-aperture setting for increased sharpness and image quality. Often a circular polarising filter, which absorbs up to two stops of light, is enough, however if not then a solid ND filter may be needed. Here, a 0.9ND filter combined with a polariser takes the shutter speed from 1/25sec to one second. A 0.9ND grad filter is then used to balance the sky with the ground.
4 Timing the exposure
Now it’s a waiting game – time your shots for when there’s a good, steady flow of people moving past, avoiding times when people stop in one position too long. A remote release is your best friend here – if people see you poised with your finger on the shutter they might stop mid-frame, or (if they’re trying to be courteous) stand beside you waiting for it to be clear. Using a remote and looking away from your camera tends to keep the crowd moving.