Rather unscientific test using RX100II (same sensor as RX10) as baseline compared to GH3. Lumix 12-35 f2.8 & 20mm f1.7. Same low-light scene. Both cameras 24p, Manual Movie Mode, Exposure meter set to "0"
...Now did the footage from both cameras look identically exposed ?
It's not uncommon for some cameras to under or over expose compared to another model, so we need to look at the recorded image to confirm that the exposure is the same.