Sigma SD1 has a
15.0MP APS-C (24 x 16 mm ) sized CMOS (Foveon X3) sensor and features Dual True II processor. On the other hand, Fujifilm X-A2 has a
16.0MP APS-C (23.6 x 15.6 mm ) sized CMOS sensor and features EXR Processor II processor.
Another difference between these two cameras is that Sigma SD1'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 SD1 and X-A2 sensor size comparison.
Sensor Size and Resolution Comparison image of Sigma SD1 and Fujifilm X-A2 Cameras
Sigma SD1 and Fujifilm X-A2 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
Sigma SD1
or the
Fujifilm X-A2 ,
including hyperfocal distance.
