Fujifilm X100T has a
16.0MP APS-C (23.6 x 15.8 mm ) sized CMOS X-TRANS II sensor and features EXR Processor II processor. On the other hand, Sigma SD1 Merrill has a
15.0MP APS-C (24 x 16 mm ) sized CMOS (Foveon X3) sensor and features Dual True II processor.
One other difference between these two cameras that is worth mentioning is that Sigma SD1 Merrill'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 X100T and SD1 Merrill sensor size comparison.
Sensor Size and Resolution Comparison image of Fujifilm X100T and Sigma SD1 Merrill Cameras
Fujifilm X100T and Sigma SD1 Merrill 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 X100T
or the
Sigma SD1 Merrill ,
including hyperfocal distance.
