I've recently taken hold of a new Sony A7r II. I've used it on a couple of photography jobs, played around with it a fair amount and I'm happy to report I've been very impressed with it as a pro use camera on commissions. I wanted to try a side by side comparison of the Sony A7rII next to my Pentax 645Z. Looking at the everyday raw files coming out of the Sony I was interested to see how they stacked up against the Pentax. The Pentax is well regarded as having one of, if not the best performing sensor in any camera available today. It's worth bearing in mind that the Sony costs roughly £2500 whilst the Pentax comes in at around £7000 (bodies only).

For an additional comparison I've added in my workhorse of the last couple of years, the 5d mkIII. This is by no means scientific or precision testing, I'll happily admit it's quick and dirty, but it is close to a real world example of my everyday shooting.

I took my three pro cameras: the Sony A7r II, Pentax 645z and the 5d mk3 and attempted a side by side comparison of their RAW image quality. In the first test I shot with a wide aperture at low ISO. In the second test the images are underexposed by three stops and recovered in post. The final set up is a straight high ISO test to see how they all behaved shooting a very contrasty scene.

With the cameras tripod mounted, the first shots were shot at 100 ISO, f/2.8 and 1/125 with a large flash right of camera. The Sony and the Canon have a Canon 50mm f/1.2 (Meta-bones Adapter MK IV on the Sony) and on the Pentax I used a 55mm f2.8 (equivalent to 45mm focal length on full frame 35mm). The focal distances and ratios are not identical but close enough to get a real world idea.