Digital Camera World (2019-06)

60 DIGITAL CAMERA^ JUNE 2019 http://www.digitalcameraworld.com

CAMERA COLLEGE

uses in general photography – from

illuminating rocks, flowers or other objects

in the foreground of a landscape to opening

up the shadows in an interior shot. The

principle is always the same, regardless of

the subject: set an exposure that retains

detail in the brighter parts of the scene –

a technique known as ‘exposing for

the highlights’ – and use flash to

fill in the shadow detail.

While the idea behind fill-flash is to

supplement existing lighting rather than

replace it, it’s certainly worth experimenting

with the strength of the exposure for both

the flash and the background. ‘Intelligent’

TTL systems in modern cameras do well

at adding the right amount of flash, but you

may want to add just a hint of fill light, for

instance, so it is almost imperceptible that

flash had been used. Alternatively, you

may choose to have the flash overpower

the existing light for a more dramatic effect.

By underexposing the background you can

create some striking results, particularly if

you’re shooting outdoors, although you will

need a powerful flashgun to achieve the

effect on a clear summer’s day. Be sure

to pack extra batteries too, as the flash

will be firing at or near full power when

you’re trying to overpower the sun.

While the idea behind

ˡǼǼٮˢƏɀǝǣɀɎȒɀɖȵȵǼƺȅƺȇɎ

the existing lighting rather

ɎǝƏȇȸƺȵǼƏƬƺǣɎًƺɴȵƺȸǣȅƺȇɎ

ɯǣɎǝɎǝƺɀɎȸƺȇǕɎǝȒǔɎǝƺ

ƺɴȵȒɀɖȸƺǔȒȸƫȒɎǝɎǝƺ

ˢƏɀǝƏȇƳɎǝƺƫƏƬǸǕȸȒɖȇƳ

IȸȒȇɎƏȇƳȸƺƏȸƬɖȸɎƏǣȇɀɵȇƬ

You may able to capture more natural-looking results when you shoot in low light

The shutter mechanism

inside an SLR is typically

constructed from two sets of

metal-bladed shutters. These

prevent light from reaching

the imaging sensor until you

take a picture. By default, a

flash fires once the first set

of shutters has moved out of

the way to expose the sensor.

This is known as ‘first curtain

sync’ or ‘front curtain sync’,

and it allows you to fire the

flash at a precise moment.

The drawback of the

flash going off at the start

of the exposure is that any

movement during the rest of

the exposure will appear as

a blur in front of the flash-lit

subject – making it appear to

be reversing at high speed!

Many cameras and

flashguns give you the option

to select ‘second curtain sync’

or ‘rear curtain sync’. Here,

the flash is triggered at the

end of the exposure. Any

movement recorded at the

start of the exposure will now

appear as a blurred trail

behind the sharp, flash-lit

subject, giving a more natural-

looking result. Timing is the

big problem with this flash

mode, as the subject may

have moved out of position

• or out of the picture – by
  the time flash fires.

First curtain sync

The short duration of the flash freezes a moving subject

as you press the shutter release. But as the subject

continues to move away from the point that the flash

fired, motion is recorded as a blurred trail in front of it.

Second curtain sync

You’ll need to know where your subject is going to

be towards the end of the exposure when you use

this option, which can be tricky when you’re using

a digital SLR that has a blacked-out viewfinder.

Should you make the switch?

The main flash fires

at the end of the long

exposure, so blur appears

behind the subject.

The flash fires at the

start of the exposure;

motion blur from

the longer exposure

appears in front

of the subject.

Double ‘closes’ on

second curtain

Second curtain closes

First curtain opens

First curtain opens

A pre-flash may

fire just after the

shutter opens