Canon SX30 IS has a
14.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features Digic 4 processor. On the other hand, Nikon S3300 has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor .
Below you can see the SX30 IS and S3300 sensor size comparison.
Canon SX30 IS and Nikon S3300 have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture. On the other hand, since Canon SX30 IS has 14% larger pixel area compared to Nikon S3300, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.