Olympus SZ-30MR has a 16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor and features TruePic III+ processor. On the other hand, Olympus TG-1 iHS has a 12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features TruePic VI processor.
Below you can see the SZ-30MR and TG-1 iHS sensor size comparison.
Olympus SZ-30MR and Olympus TG-1 iHS have 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 Olympus TG-1 iHS has 35% larger pixel area (2.38µm2 vs 1.76µm2) compared to Olympus SZ-30MR, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.