Canon Camera Hackers Manual page 170

rem compute distances in mm
select b
case 0;
case 1;a = a * 10
case_else a = a * 100
end_select
select d
case 0;
case 1;c = c * 10
case 2;c = c * 100
case_else c = -1 rem infinite
end_select
The next instructions are used to turn the automatic flash off. Flash illumi-
nation is not really desirable for DOF stacking. In addition, the flash opera-
tion can make the script behave unpredictably because of the time needed
by the camera to recharge the flash. So, we store the current flash mode
into variable m and then call subroutine fmode. The desired flash mode (2 for
off) is set to transfer variable M.
rem turn off flash
m = get_flash_mode
M = 2
gosub "fmode"
Then, the shutter button is half-pressed. This is done to determine the cor-
rect exposure. If the camera is in autofocus mode, the focus distance is also
determined. The subroutine prep waits until the camera is ready to shoot.
The focus distance is retrieved and kept in variable z so that we can later
restore the focus. We also retrieve the hyperfocal distance and keep it in
variable y.
As a final preparation step, we lock the autofocus. During the following
shots, the autofocus facility will not be used. This includes the AF light, too,
which will not be illuminated.
press "shoot_half"
rem focus and exposure
gosub "prep"
z = get_focus
y = get_hyp_dist
print "Prior distance:",z
set_aflock 1
5.7 Example scripts
161