To determine the correct aperture for flash
photography. get the "guide number" of the
flash bulb you are using. Then make this simple
computation:
=
Aperture Setting IF·stop)
For example. when flash bulb guide number is
80 (in feet) and the distance to the subject is
10
feet (with ASA 100 film, using shutter speedor
1I60th
sec.),
the F·stop is:
~g
=
8
NOTE:
• When using M·c1ass flash bulbs, a shutter
speed of
1/15th
sec. or slower is recorn-
mended.
• Use "blue" flash bulbs generally for color
photography.
Guide ,"umber
Distance to Subiect
To Next Page
Loading...
