Image capture is where all the new technology in the A7 III makes it stand out from the A7 II. For starters, the A7 III has more than doubled the number of autofocus points, with 693 phase detect AF points covering approximately 93% of the image and 425 contrast detect points. The A7 II on the other hand, has 117 phase detect points and only 25 contrast detect ones.
Safe to say, the difference in focus speeds is immense. The A7 III obtained focus faster in all of our testing, and the wider spread of AF points allowed it to more accurately track subjects as they moved across the frame. Sony calls this 4D focus, and it essentially takes advantage of the faster processing capabilities to read AF points at a higher frequency for better tracking.
The new sensor design also greatly tilts the scales in favor of the A7 III in terms of continuous capture as the camera not only captures faster, but also performs at a higher rate for a longer duration. So, add that with the improved focus speed (and tracking) we just mentioned above, and it’s easy to see how the A7 III handles fast-moving action better than the A7 II. For the rare times when the camera doesn’t land a focus point exactly on the subject of your image, there’s still the focus lever for quicker adjustments. That certainly beats using the four-way joystick.
The newer camera also has the edge in terms of color accuracy, producing images that are truer to life straight-out-of-camera JPEGs. The colors from the A7 II are quite a bit cooler in comparison, as you’ll see in the image above. Though both cameras have almost identical resolution numbers, it does seem like the A7 III is resolving slightly more detail than the A7 II too. The result of an improved image stabilization engine and a new processor perhaps?
The A7 III has a native ISO range of 100-51,200 compared to the A7 II which has a native ISO range of 100-25,600. That’s a one-stop difference, and it shows. Look at the two images above, and you’ll see that there is clearly more detail on the label of the bottle. Images from the A7 III at ISO 25,600 are still salvageable. And you have the option to move up to ISO 51,200 as the images from the A7 III while grainy, still maintain a good amount of detail – more detail than images from the A7 II at ISO 25,600 even!
We also pulled up images from the APS-C sized Fujifilm X-H1 to see how the cameras (or more accurately, sensors) compared, given the A7 II was released back in 2014, and the X-H1 had a smaller sensor. In all cases the A7 III performed best as expected from the newer, larger sensor. But while the A7 II had a very slight edge in terms of low ISOs, the X-H1 was quite clearly better above ISO 25,600, so the gap in performance between sensor formats probably isn’t as large as the marketing speak might have you think.