Canon A490 has a
10.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor . On the other hand, Canon SD1300 IS has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features Digic 4 processor.
Below you can see the A490 and SD1300 IS sensor size comparison.
Canon A490 and Canon SD1300 IS 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.