zsoumyaThe megapixels are low because the pixels (photosites) on the sensor are much bigger but occupying the same sensor space, to allow more light to be taken in. Hence it's unparalleled low light performance. Check some reviews.
zsoumyaWhat @Digital_Dub said. The A7R is the camera to go with if you're concerned with a high-megapixel camera. This one is designed to essentially have huge pixels, which on a full-frame sensor and the extended ISO range, basically equates to night vision with this monster.