Well... yes and no. CHDK can override both shutter speed and aperture, but the SD 1000, like most (all ?) ixus/IXY models
doesn't have an iris diaphragm, but a neutral density filter instead; CHDK can control it's setting, but you'll never get more
than 2 'aperture' settings (at any given zoom setting).
Read more about your cam's features with/without CHDK here:
CameraFeatures - CHDK Wikihope that helps,
wim
