Digital Camera World (2019-06)

JUNE 2019 DIGITAL CAMERA^59

CAMERA COLLEGE

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Using fill-flash on a sunny day can lead to exposure problems, but there are several options open to you

If you want to use flash in

bright daylight, shutter speed

becomes a key consideration. The

entire surface area of the imaging

sensor needs to be fully exposed

when the flash fires, and this only

happens at the camera’s flash sync

speed or slower. But a brightly lit

scene may require a much faster

shutter speed to expose it correctly.

For example, if the exposure

required to record a portrait is

1/3,200 sec at f/2.8, but the flash

sync speed is 1/200 sec, then you

have a problem. Depending on the

shooting mode, your camera may

end up setting the slower flash sync

speed (and making the image four

stops too bright) or only record

part of the scene correctly.

APERTURE FREEDOM

You can set a large aperture

to blur the background,

although you may need

to move the flash closer.

THE RESULT

The backdrop of your

photo may be distracting

at smaller apertures, but

at least the exposure is OK.

OVEREXPOSED PARTIALLY EXPOSED

ADDED IMPACT

To get a similar look with high-

speed sync, put the flashgun

on a stand close to the subject

and trigger it remotely.

OPTION 1
Use a smaller aperture
You could decrease the size of the aperture until
the shutter speed reaches the flash sync speed.
This does increase the depth of field, however,
which is not always ideal for a portrait, as well
as reducing the distance the flash can reach.

OPTION 2
Use high-speed sync
Many flashguns now include this feature,
which lets you use a shutter speed on the
camera that’s faster than the flash’s sync speed.
The flash will pulse rapidly during the exposure,
to match the position of the slit between the
shutter curtains as it moves in front of the sensor.

Reduced power

The faster the shutter speed, the

more the flash power is reduced,

so you may have to move closer.

Distance

Flash power is less compromised than

with high-speed sync, so you may be

able to shoot from further away with a

longer lens for a more flattering result.

OPTION 3
Use a filter on the lens
Neutral-density and polarising filters reduce the
total amount of light coming through the lens,
so you can achieve slower shutter speeds at larger
aperture settings. Filter strength is rated in stops,
with each stop doubling the exposure time. For
instance, you’d need a four-stop ND filter to reduce
a shutter speed of 1/3,200 sec to 1/200 sec.