Install:
apt-get install gphoto2
visudo:
www-data ALL = NOPASSWD: /usr/bin/gphoto2
Example:
gphoto2 --auto-detect
gphoto2 --list-all-config
gphoto2 --capture-image-and-download --camera="Canon PowerShot A520 (PTP mode)"
gphoto2 --set-config zoom=0 --set-config imagequality=2 --set-config aperture=53 --capture-image-and-download --filename `date +%Y%m%d%H%M%S`.jpg
PHP: