Canon SX210 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 SX220 HS has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features DIGIC 4 with iSAPS technology processor.
Below you can see the SX210 IS and SX220 HS sensor size comparison.
Canon SX210 IS and Canon SX220 HS 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.