Sigma SD1 Merrill 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 X100S has a
16.0MP APS-C (23.6 x 15.8 mm ) sized CMOS X-TRANS II sensor and features EXR II processor.
Another similarity between these two cameras is that both Fujifilm X100S and Sigma SD1 Merrill sensors lack anti-alias (Low-Pass) filters. 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 Merrill and X100S sensor size comparison.
Sensor Size and Resolution Comparison image of Sigma SD1 Merrill and Fujifilm X100S Cameras
Sigma SD1 Merrill and Fujifilm X100S 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 Merrill
or the
Fujifilm X100S ,
including hyperfocal distance.
