Minutes-long
exposures
ND filters
A neutral density filter slows the flow of light
into the camera, thereby letting us extend
our exposure length even further. The
stronger the filter, the longer the exposure.
Here the combination of a three-stop filter,
a narrow aperture of f/16 and a low ISO of
100, means we can keep the shutter open
for over 10 minutes!Close the viewfinder
Whenever you use an exposure that runs into several
seconds or more there’s a danger that light may seep
in through the viewfinder and cloud the exposure. So
be sure to close up the viewfinder or block it to stop
light from entering from the rear.
Compose beforehand
It can be tricky to see through a DSLR
viewfinder after attaching a strong ND filter,
especially at twilight when the light levels
are low. So if necessary compose the frame
before attaching the lens. Alternatively,
switch to Live View for a brightened view
of the scene (you may need to turn off the
exposure preview setting).Using Bulb
Most cameras max out at a 30-second
exposure time. If you want to go beyond this
you need to use Bulb mode so that the
shutter stays open as long as the shutter
button is engaged. The term ‘bulb’
references a time when shutters were
opened and closed by squeezing a rubber
bulb of compressed air attached to a hose.
Narrow aperture
If your near-dark scene includes lights like
those shining on the windmill here, then
use a narrow aperture. As well as offering
greater depth of field and longer shutter
speeds, the high f-number also results in
star-like streaks around specular highlights.
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(^234)
2
Live View
Your autofocus may struggle to lock on
in low light – especially after attaching
an ND filter – so it’s often easier to
focus manually using Live View. Switch
the lens to manual focus, turn on Live
View and zoom in to the scene then
adjust the focus ring until it’s sharp.
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Shoot after dark