UBASIC/Scripts/CanonA640: EV Bracketing

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[edit] EV Bracketing

Written for/on: Canon A640

Also works on: Other Canon AXXX (Not tested)

EV Bracketing by Johan Van Barel (http://www.vanbarel.com)

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)
• Initial Delay (Sec) (Default=1)

---

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 (Select P Mode)
@param a Number of Pics
@default a 3
@param b EV Step Size (1/3 EV)
@default b 3
@param c Initial Delay (Sec)
@default c 1

if a<2 then let a=2
if b<1 then let b=1
if c<0 then let c=0

print "Pics:"; a, "Step:"; b

sleep c*1000

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