Canon SX230 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. On the other hand, Canon ELPH 520 HS has a
10.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features DIGIC 5 processor.
Below you can see the SX230 HS and ELPH 520 HS sensor size comparison.
Sensor Size and Resolution Comparison image of Canon SX230 HS and Canon ELPH 520 HS Cameras
Canon SX230 HS and Canon ELPH 520 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.
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Canon SX230 HS
or the
Canon ELPH 520 HS ,
including hyperfocal distance.