ISO sensitivity / low light
1 2 3 4 5 6 7 8 9 10

ISO sensitivity / low light

Even at ISO 12,800, the a7R II's Raw files contain bags of detail, and more dynamic range than the a7 II. When normalised at 24MP, the higher-resolution a7R II also offers superior perceptual detail and lower noise levels than the a7 II. As well as image quality, the a7R II scores over the older camera again in terms of low-light AF performance.

In the good old days, it was generally believed that the more pixels you packed onto a sensor, the noisier the images you'd get out the other end. These days of course we're much more enlightened, and as we all know, the idea that more pixels = more noise isn't necessarily true. And everybody is happy now because we all understand that pixel-level noise isn't the whole story, and the time we used to spend arguing about such things on the Internet we now spend with our families, when we're not out in the sunshine taking photographs.

Only some of that last sentence is true, but what is true is that despite having almost twice as many photo-sites as the a7 II, the 42MP a7R II offers superior high ISO image quality. When files are normalized to 24MP and viewed side-by-side, the a7R II offers at least one stop better perceptual image quality in terms of Raw noise levels, and in terms of detail retention it's more like two stops better than its 24MP cousin, thanks to a significantly improved JPEG engine that's class-leading at balancing noise reduction and sharpening.

Part of the reason for this performance gap is simply the fact that the a7R II's sensor is a couple of years newer than a7 II's, and sensor technology (especially at Sony) moves quickly. But fundamentally, the sensor in the a7R II is of a very different design. BSI-CMOS sensors move a lot of per-pixel electronics to the back of the sensors, out of the way, so they're more efficient when it comes to converting photons into usable signal. As such, the a7R II isn't just better than the a7 II, it's better than almost every other full-frame camera we've ever tested. Up to around ISO 25,600 it even holds its own (when files are normalized at 20MP) against the Nikon D5.