Both Hasselblad X1D and Pentax 645Z have Medium format sized 51.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
One other difference between these two cameras that is worth mentioning is that Pentax 645Z'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 X1D and 645Z sensor size comparison.
Sensor Size and Resolution Comparison image of Hasselblad X1D and Pentax 645Z Cameras
Hasselblad X1D and Pentax 645Z 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
Both Hasselblad X1D and Pentax 645Z sensors have been tested by DxoMark. DxoMark 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. Of the two cameras that we are comparing, X1D has scored 102, 1 points higher than 645Z.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Hasselblad X1D
102
26.2 bits
14.8 Evs
4489 ISO
Pentax 645Z
101
26.0 bits
14.7 Evs
4505 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
Hasselblad X1D
or the
Pentax 645Z ,
including hyperfocal distance.
