Lighting System

Benefit 1: High light output

External flashes deliver more light, covering greater distances and wider areas

External flash (GN 43)

Built-in flash (GN 6)

In order to get everyone in the shot the photographer had to shoot from a distance of about 5 meters. The photo taken with the camera's built-in flash is too dark, while the version shot with the external flash is well lit throughout the image area.

Give yourself the freedom to use distance as a creative tool

Built-in camera flashes won't provide sufficient light when you have to move away from your subject or cover a wide area. You might have to put a little distance between yourself and a group in order to get everyone in the frame, for example, and often you'll find that the camera's built-in flash just doesn't deliver enough light.

Tech Note Flash guide numbers (GN)

“Guide Numbers” specify a flash unit's ability to illuminate subjects at a distance. The guide number is equal to the maximum flash-to-subject distance multiplied by the appropriate aperture F-number.

Guide Number (GN) = distance (m) x aperture (F-number)

A guide number of 60 (in meters at ISO 100), for example, means that a subject 15 meters away will be properly illuminated with an aperture setting of F4 (60 = 15 x 4). If you decrease the aperture size to F8, the distance will be halved so that subjects at a maximum distance of 7.5 meters (60 = 7.5 x 8) will be properly illuminated.

Maximum distances with F4, ISO 100 sensitivity

Maximum distances with F4, ISO 100 sensitivity: (1) Built-in flash (α77(GN 12)) : approx. 3 meters; (2) HVL-F43AM (GN 43) : approx. 10.75 meters; (3) HVL-F60M (GN 60) : approx. 15 meters; * The GN number is also affected by lens focal length and F-number. Refer to the specifications of the flash used for details.