Panasonic S1R has a
47.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Venus Engine processor. On the other hand, Nikon S570 has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features Expeed processor.
Panasonic S1R's sensor provides 35MP more than Nikon S570's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Another difference between these two cameras is that Panasonic S1R's sensor lacks anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moiré occurring in certain scenes.
Below you can see the S1R and S570 sensor size comparison.
As seen above, Panasonic S1R has a 30.8x Larger sensor area than Nikon S570. 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.