Both Canon 50D and Pentax K-7 have APS-C sized 15.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the 50D and K-7 sensor size comparison.
Sensor Size and Resolution Comparison image of Canon 50D and Pentax K-7 Cameras
Canon 50D and Pentax K-7 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.
DxOMark Sensor Scores
Both Canon 50D and Pentax K-7 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, 50D has scored 63, 2 points higher than K-7.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Canon 50D
63
21.8 bits
11.4 Evs
696 ISO
Pentax K-7
61
22.6 bits
10.6 Evs
536 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
Canon 50D
or the
Pentax K-7 ,
including hyperfocal distance.
