Both Pentax 645Z and Hasselblad X1D have Medium format sized 51.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Another difference between these two cameras is that Pentax 645Z'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 645Z and X1D sensor size comparison.
Sensor Size and Resolution Comparison image of Pentax 645Z and Hasselblad X1D Cameras
Pentax 645Z and Hasselblad X1D have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture.
DxOMark Sensor Scores
DxOMark is a benchmark that scientifically assesses image quality of camera sensors. It scores camera sensors for color depth (DXO Portrait), dynamic range (DXO Landscape) and low-light sensitivity (DXO Sports), and also gives them an overall score. Pentax 645Z and Hasselblad X1D sensors have been tested by DxO and the results show that X1D has a better overall score of 102, 1 points higher compared to 645Z's score of 101.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Pentax 645Z
101
26.0 bits
14.7 Evs
4505 ISO
Hasselblad X1D
102
26.2 bits
14.8 Evs
4489 ISO
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
Pentax 645Z
or the
Hasselblad X1D ,
including hyperfocal distance.
