May, 2012 timefocus.bas / "SHUTTER & FOCUS STACKING" is a combined depth-of-field (focus) stacking and exposure bracketing script for CHDK. Written for and tested on the Powershot S3IS, it should be portable to other models by changing the test-values of only two lines which interpret the Mode Switch position. Before entering mode you should: Choose your script shoot delay based on whether you have a remote for your camera. If you do, you probably don't need any delay; if not, a couple of seconds will give time for any vibrations to end after you take your finger off the shutter button.