Benefits of using flash
Stops motion of moving subjects (burst usually
between 1/1000 second and 1/8000 second)
Prevents blur caused by hand holding
Portable, predictable, measurable, repeatable
Very consistent in brightness and color
Flash Facts Everyone Must Know!
Every flash exposure is two exposures in one.
Aperture controls flash – Shutter speed controls
Flash exposure is not affected by shutter speed
(except when using “high speed sync).
Flash illumination is dramatically affected by
distance (inverse square law, aka “falloff”).
Cameras measure ambient light and flash
More Facts Everyone Must Know!
Every SLR camera with a mechanical focal
plane shutter has a maximum flash shutter speed
(1/250 second on current DSLRs).
High Speed Sync allows you to use wide
apertures and fast shutter speeds while still using
f-stop = GN / distance or Distance = GN / f-stop
A Guide Number must contain a distance unit
and an ISO value (580EX II: 190 feet / 58 Meters
at ISO 100).
Basic Flash Techniques
The easiest way to light a scene with flash is with direct
flash on a camera (a built in or flash unit mounted directly
on the camera and pointed directly at the subject).
Although this will produce a properly exposed
photograph, they tend to be flat (in modeling and
texture), shadowless, and two dimensional
The reason for this is not a fault of the flash, but its position
in relation to the lens (the cause of red eye too)
A flash that you can use from off camera offers more
Basic Flash Techniques cont…
Control is limited when using a built in flash,
A small flash units that connect to the camera’s hotshoe
allows far greater control.
Most hotshoe flash units have a swivel head which allows
you to bounce the flash off a wall or a low ceiling,
diffusing the light to give the subject softer shadows.
Flash bursts are too short to see how the light will be
recorded on film so carefully aim the flash at your subject.
The use of a flash meter may also be necessary.
Basic Flash Techniques cont…
By taking the flash off camera and altering its
position, various lighting styles can be achieved to
produce more natural looking results with a less
obvious “flash” look.
Holding the flash above the subject more closely
resembles natural lighting and increases the feeling
Manual mode means on automatic flash units
means full power. Some have manual control
settings such as ½, ¼, 1/8, 1/16, 1/32, 1/64 and
When using the automatic Thyristor feature, you
must select one of the available aperture
settings as indicated by the flashes “calculator”
and set it manually. The flash will measure the
light reflected from the subject during the
exposure and cut off the flash when exposure is
correct. You must remain within the specified
distance range displayed in the “calculator”.
TTL and E-TTL
TTL stands for Through The Lens. It works exactly
like and automatic flash except it uses the
camera sensor/meter (instead of a flash
mounted thyristor) to adjust the flash power for
E-TTL stands for Evaluative Through The Lens. It
uses a brief pre-flash before the main flash in
order to obtain a more correct exposure.