Fujifilm X-A3 has a
24.0MP APS-C (23.5 x 15.7 mm ) sized CMOS sensor and features EXR Processor II processor. On the other hand, Fujifilm X-T30 III has a
26.0MP APS-C (23.5 x 15.6 mm ) sized X-Trans CMOS sensor and features X-Processor 4 processor.
One other difference between these two cameras that is worth mentioning is that Fujifilm X-T30 III's sensor doesn't have an 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 X-A3 and X-T30 III sensor size comparison.
Sensor Size and Resolution Comparison image of Fujifilm X-A3 and Fujifilm X-T30 III Cameras
Fujifilm X-A3 and Fujifilm X-T30 III 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
Fujifilm X-A3
or the
Fujifilm X-T30 III ,
including hyperfocal distance.
