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, Canon 650D has a
18.0MP APS-C (22.3 x 14.9 mm ) sized CMOS sensor and features Digic 5 processor.
Below you can see the SX30 IS and 650D sensor size comparison.
As seen above, Canon 650D has a 11.8x Larger sensor area than Canon SX30 IS. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.