Below you can see the front view size comparison of Nikon P7800 and Canon G5 X. Canon G5 X is clearly the smaller of the two cameras. Its body is 7mm narrower, 2mm shorter and 6mm thinner than Nikon P7800.
Nikon P7800 vs Canon G5 X - Front View
Nikon P7800 vs Canon G5 X - Top View
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.
Camera Size Comparison
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