Pentax MZ-60 Operating Manual page 90

88
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 slower than
1/100 can be set. In this mode, the exposure of the
background can be controlled by the manual exposure while
the flash properly exposes the foreground subject.
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*
MEMO
• When the distance to the subject is less than 0.7m (2.3ft), the flash cannot be
used. If the flash is used less than 0.7m, it causes vignetting in the picture
corners, light is distributed unevenly and the picture may be over exposed.
• *The value 5 used in the formula above is fixed value applied to the built-in flash
in this camera.
The guide number (GN) depends upon the film speed used as
shown below.
ISO25 GN5.5
ISO50 GN7.8
ISO100
Exp. If an ISO100 film is used at an aperture of f/3.5, the flash
effective distance is obtained as follows:
For maximum distance Guide Number (11) ÷ f/3.5 = 3.14m
For minimum distance
* Minimum distance of the built-in flash in this camera
Thus, the flash effective distance is from approx. 0.7m to 3.14m.
ISO200
ISO400
GN11
GN15.6
GN22
3.14 ÷ 5 = 0.63m 0.7m *