Below you can see the front view size comparison of Sigma Quattro H and Sony A7R IV. Sony A7R IV is 18mm narrower and 13mm thinner than Sigma Quattro H but it is also 1mm taller.
Sigma Quattro H vs Sony A7R IV - Front View
Sigma Quattro H vs Sony A7R IV - Top View
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.
Camera Size Comparison
Select Two Cameras for Size Comparison