Pentax 57233 manual Metered Manual Mode

112

ADVANCED OPERATION FOR THE BUILT-IN FLASH

4.Metered Manual Mode

•When using the built-in flash in the Metered Manual Mode, any combination of aperture and shutter speed 1/125 or slower can be set. In this mode, the exposure of the background can be controlled by the manual exposure to take a flash photograph.

1.Calculating the flash effective range according to the camera- to-subject distance.

Maximum flash distance = Guide Number ÷ Selected aperture Minimum flash distance = Maximum flash distance ÷ 5*

*The value 5 used in the formula above is a fixed value applied to the built-in flash in this camera.

✍MEMO

•When the distance to the subject is less than 0.7m (2.3ft), the flash cannot be used. If the flash is used within 0.7m, it causes vignetting in the picture corners, light is distributed unevenly and the picture may be over exposed.

The guide number (GN) depends upon the film speed used as shown below.

ISO25	GN5.5		ISO200	GN15.6
ISO50	GN7.8		ISO400	GN22
ISO100		GN11