Canon EOS 5D vs Canon PowerShot S3 IS digital cameras comparison
Screen size at Canon EOS 5D is quite larger with its 2.5" than Canon PowerShot S3 IS with its 2".
Canon EOS 5D is able to produce nicer pictures since it has 12.8 megapixel picture quality, comparing to 6 megapixels at Canon PowerShot S3 IS.
Canon EOS 5D comes without lenses (optical zoom) and you should buy some external for this professional model. Canon PowerShot S3 IS has lenses with optical zoom 12x.