Olympus 7030 has a
14.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features TruePic III processor. On the other hand, Olympus TG-4 has a
16.0MP (1/2. ) sized BSI-CMOS sensor and features TruePic VII processor.
Below you can see the 7030 and TG-4 sensor size comparison.
As seen above, Olympus 7030 has a infx Larger sensor area than Olympus TG-4. 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.