Sony FX9 has a
19.0MP Full frame (35.7 x 18.8 mm ) sized CMOS sensor . On the other hand, Sony A7S III has a
12.0MP Full frame (35.6 x 23.8 mm ) sized BSI-CMOS sensor and features Bionz XR processor.
Sony FX9's sensor provides 7MP more than Sony A7S III'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.
Below you can see the FX9 and A7S III sensor size comparison.
Sensor Size and Resolution Comparison image of Sony FX9 and Sony A7S III Cameras
As seen above, Sony A7S III has a 1.3x Larger sensor area than Sony FX9. 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.
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
Sony FX9
or the
Sony A7S III ,
including hyperfocal distance.
