>>3770591The larger pixels get more light. But the 40mp FF sensor also gets more light in total. At the same equivalent focal length the FF will still be better in terms of noise by the same amount as a 10mp FF sensor as the FF sensor is still getting a lot more light in total regardless of pixel size.
Sensor size has a way bigger impact than pixel size. With a 40mp FF sensor you’re just subdividing the pixels but they still add up to the same amount of light (slightly less due to gap loss perhaps), it’s only as noisy as the MFT sensor at the pixel level, not at the image level. As the image signal is magnified larger above the pixel noise level than it is on the MFT sensor.
A7rIV vs a 16mp MFT sensor is a good example, similar pixel size. The FF sensor doesn’t perform better because it lets you have larger pixel sizes, it performs better because it’s larger and collects more light (light = signal) overall which is independent of pixel size. The impact of sensor size is much greater than the impact of pixel size.
>>3770583Yes, same lens and same f-stop = more light on an APS-C sensor area vs MFT size area. You may not notice it at base ISO, but you may notice extra detail of which ever has more resolution.
