There's something different about the way the A7R III feels in your hand compared to the A7R II, and on closer inspection it turns out the new camera is 73.7mm thick, compared to the 60.3mm of the old model. Part of that is due to a slightly larger grip, and part from a slightly thicker back section. It's an observation rather than a criticism. Otherwise, the A7R III shares the same remarkably small frontal area as previous models.
That's a good thing if you want the most compact camera possible, but there is a caveat. Sony's camera bodies might be small, but its lenses – especially its good ones – certainly aren't. These are just as big as comparable full-frame DSLR lenses, sometimes bigger, and this has two effects. First, with a lens fitted, the A7R III doesn't offer the size advantage over a full-frame DSLR that the body-only dimensions might suggest, and second, the lenses do feel a bit big for the body. We tried the A7R III with Sony's 24-105mm f/4, 16-35mm f/2.8 and 70-200mm f/2.8, and while it's perfectly manageable with these big lenses, action or portrait shooters might want to look at the Sony VG-C3EM grip to make the camera-lens combination a bit more wieldy.
The rear screen tilts up and down but isn't fully articulated, so it's fine for horizontal shooting at all sorts of angles, but less flexible when the camera is held vertically.
The electronic viewfinder is crisp and lag-free, but doesn't give a very good representation of the dynamic range the camera will capture. There's a general assumption that electronic displays will give an accurate rendition of what the sensor will capture, but that's only true as far as the ability to simulate exposure, white balance and image effects are concerned. It's a digital display like any other, and this one is pretty contrasty and could make you think shadows and highlights are clipped when actually they aren't.
The A7R III's shift towards action photography gets a boost with a new multi-selector on the back of the camera to set the focus point/area position. Alternatively, you can tap on the screen to set the focus point.
Both worked fine, though the autofocus options in general are not for the faint-hearted. This is a professional camera aimed at professional users, so you might not expect any particular beginner-friendliness – but even experienced photographers will need to spend some time with the manual – and with the camera out in the field – to find the autofocus settings that best suit the way they work.
Apart from the autofocus mode itself – single shot, continuous AF or automatic selection – there's a choice of five AF point modes, including Wide (automatic selection within the whole AF area), Zone (automatic selection within a smaller zone), Center, Flexible Spot (which you can move around the frame) and Expand Flexible Spot (uses focus points around the selected spot).
It doesn't stop there. All five are available under an additional Lock-On AF mode, where the AF system will track your initial locked-on subject within the zone/area you've selected.
It sounds complicated but it doesn't take too long to grasp the principles and to pick out the modes which sound like they might work best for you, but it might a good deal longer to check and compare the results with real-world subjects, which don't all behave in a predictable fashion.
For our tests we recruited the help of a kenshi (swordsman) running through a series of kenjutsu patterns which combined movement across the frame and towards the camera. We wanted to find out how well the AF system could track the mask on the helmet and keep that sharp as the key point of focus through these fast and complex movements.
In fact the A7R III kept up pretty well, though each AF zone had its pros and cons. The Flexible Spot mode was best for keeping the mask in focus, provided we kept the AF point in the right place – but that wasn't easy with sudden lateral movements and sword strokes in front of the mask. Using a wider focus zone and focus tracking took the pressure off accurate focus point positioning and allowed a steadier camera position, but if the subject left the zone the AF defaulted to the background, and in some instances the camera lost focus completely for a frame or two for no obvious reason.
Photographing moving subjects demands a good deal of skill, anticipation and practice on the part of the photographer. The A7R III's AF system responded well with a really tough subject, with a good hit rate of in-focus shots, but confirmed that skill, practice and luck are part of the equation too.
A new multi-selector 'thumbstick' on the rear makes it easy to shift the focus point while you're using the viewfinder, or you can use the touch-sensitive rear screen. And if you like to separate the shutter release from the autofocus actuation – and many sports photographers do – there's now an AF-ON button on the rear.