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 (http://www.hdrsoft.com/index.html)
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