Both Canon 550D and Canon 4000D have APS-C sized 18.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the 550D and 4000D sensor size comparison.
Sensor Size and Resolution Comparison image of Canon 550D and Canon 4000D Cameras
Canon 550D and Canon 4000D 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 Canon 550D and Canon 4000D 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, 550D has scored 66, 3 points higher than 4000D.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Canon 550D
66
22.0 bits
11.6 Evs
807 ISO
Canon 4000D
63
21.9 bits
11.4 Evs
695 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 550D
or the
Canon 4000D ,
including hyperfocal distance.
