Richard R writes:
I use my NEX 6 nearly all the time. Preferring its low light capacity to the more megapixels in the NEX 7.
“Low light capability” often means “did not compare fairly between cameras”. In this case, the NEX-6 might have a newer-generation sensor, so it could be a mixed situation.
In truth, all things being equal, a higher resolution sensor will have noise behavior every bit as good as the lower-res camera, and the oversampling will reduce other digital artifacts.
The mistake often made is to compare noise pixel for pixel, but this is inappropriate: when printing is done, images from two cameras having different resolutions by definition must be scaled proportionally more for the lower resolution camera. Consider a 4 megapixel camera and a 36 megapixel camera having the same per-pixel noise: the 4-megapixel camera is thus hugely more noisy for a print: its noise will be scaled by 3 times linearly (9X in area) as compared with the 36MP camera.
There are also many noise studies in DAP. Most recently in Guide to Leica, see how noise was compared for the 24MP Leica M Typ 240 versus the 18MP Leica M9.