Nikon Z30 has a
21.0MP APS-C (23.5 x 15.7 mm ) sized CMOS sensor and features Expeed 6 processor. On the other hand, Sony NEX-5T has a
16.0MP APS-C (23.4 x 15.6 mm ) sized CMOS sensor and features Bionz processor.
Nikon Z30's sensor provides 5MP more than Sony NEX-5T'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 Nikon Z30'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 Z30 and NEX-5T sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon Z30 and Sony NEX-5T Cameras
Nikon Z30 and Sony NEX-5T have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the 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
Nikon Z30
or the
Sony NEX-5T ,
including hyperfocal distance.