He was specifically speaking of DSLR.

He owns two Canon 5D MarkIIs, and he was particularly interested in the 6D to replace one of his 5Ds specifically because they kept it at 20Mpx.

When I have the chance, I'll ask him more about this. He usually is a knowledgeable guy, certainly not prone to "fanboysm", and usually speaks with some solid tech/scientific research at support of his arguments, but we did not have the chance to talk more.

I did search the topic, and I found the same you're mentioning, Andy, in "historical" terms.

But, comparing current cameras, more or less belonging to the same generation, I found my friend's point even less convincing.

If we consider the 5D Mark II and the D800, it seems to me that Canon went for the very high ISO with lower noise, while Nikon for the Very High Mpx of similar quality, but at lower ISO. This alone seems to suggest that the whole noise issue cannot be effectively simplified to the "resolution" alone. Which is obvious, maybe, but I guess what I am saying is that other factors such as the NR algorithms and the design of the sensor itself are factors that play a more important role than resolution (if we look at a specific generation of sensors/img processors/bodies).

Am I making sense?