The SD800-IS is an ultra compact digital camera with a wide angle zoom lens. It sports a 3.8x optical zoom lens with a focal length of 4.6–17.3mm (28–105mm/35mm equivalent) and an aperture range of f/2.8–f/5.8.
It’s so compact, it can fit in a shirt pocket (camera skin highly recommended so help prevent it from slipping out of the pocket).
It offers an ISO range up to top ISO speed of 1600. There is a slight improvement of ISO 400 and 800 over the SD700 but most agree that the ISO 1600 setting is useless (but always nice to have if you have absolutely no other choice).
The SD800-IS includes the new DIGIC III imaging processor, which has Face Detection Technology, fast operation and low power consumption. It records video up to 4 MB.
The SD800 is a true point and shoot camera. You can not control aperture and shutter but you can control things such as exposure compensation, white balance and saturation, sharpness and the like.