CHDK/uBASIC/Scripts/CanonA640: EV Bracketing

EV Bracketing

 * Written for/on: Canon A640
 * Also works on: Other Canon AXXX

EV Bracket by Johan Van Barel The purpose is to create a High Dynamic Range (HDR) image from a set of images taken at different exposures. The script takes a number of images around the selected EV setting. So if you take 3 pictures, with EV set to center and EV Step Size=3, it will take the first picture at -1EV, the second at Center EV and the third at +1EV. You can later stitch the images together with a program like Photomatix

Documentation/Help (save as a small EVBracket.txt" file to your /CHDK/SCRIPTS/ folder)

Select P mode on your Canon A640

Parameters: Number of Pics (Default=3) EV Step Size (1/3 EV) (Default=3)

Script Code (save as "EVBracket.bas" to your /CHDK/SCRIPTS/ folder)

rem Johan Van Barel 07-07-2007 rem EV-Bracketing for Canon A640

@title EV Bracket @param a Number of Pics @default a 3 @param b EV Step Size (1/3 EV) @default b 3

if a<2 then let a=2 if b<1 then let b=1

sleep 500

print "Bracket Pics:", a, "Step:", b click "erase" for n=1 to (a-1)*b/2 click "left" next n

print "Pic 1 of", a shoot for s=2 to a   for n=1 to b        click "right" next n   print "Pic", s, "of", a    shoot next s

for n=1 to ((a-1)*b+1)/2 click "left" next n click "erase"

end