Without hesitation or qualifiers these features of the Sony A7iii are great for my photography. The top photo is of my youngest daughter right after Christmas dinner. I took this as a series of about 6 holding the eye auto focus button and just pushed the shutter button. I saw in the viewfinder that the eye auto focus was working. The flash was set to TTL and the camera was just on Auto. I had on the Sony G 24-105 f4 lens. The camera set itself to her right eye, the Sony steady shot and OSS lens kept this shot in perfect focus. Brilliant. Did the Sony work better than I could have expected from my older cameras, yes. Did it work better than what my iPhone could have done, yes. My other cameras like the D750 or D5500 would have been able to focus on this eye if I had put the focus point on it or if I had shifted the camera focus point to where the eye was, but this would have been done by me and not the cameras. The iPhone XS Max or Sony HX80 would have found the face but not the eye. So bravo Sony. Without a doubt this is a big advancement forward and you have executed it well.
The eye auto focus on the Sony A7iii also works in a group of people.
The Sony A7iii is also easier to get mid day full sun shots with proper exposure. It is not possible to completely change the subjects to what they would look like if you had been shooting early in the day or late in the afternoon, but the Sony did allow for turning down the exposure enough not to blow all the highlights.
I went to this same location just before we went on vacation to Europe in 2017. I shot tests with my Nikon D5500, iPhone X, Minolta 600si with Kodak Gold 200. In 2017 I only was able to get the shots I liked with the film. The Nikon and the iPhone both overexposed. I could have improved my results back then if I had bracket my shots on the Nikon, but I didn’t. Film has more highlight tolerance than digital so the film was able to give very good results.
But the Sony A7iii shots above with the Zeiss 50mm f1.8 was as good as the film I shot in 2017. At this point I would be willing to say that the Sony very easily gives good mid day full sun shots better than the Nikon D5500. If I had used the Nikon D750 and also used the highlight setting I would say the results would have been similar to the Sony or the Kodak.
The Sony A7iii’s back screen moves like an iPhone or my Sony compact. It is fast and looks just like the viewfinder. This is an improvement over the DSLR’s which on the Nikons were laggy and not quick to focus. I find that I use the back screen a lot more than with the D750. The D5500 was a full on touch screen and I frequently used it when shooting landscape. I would touch the place to focus and it would set up the shot and fire away. This ability is sadly not on the Sony A7iii.
Size – The Sony A7iii is smaller than the previous full frame digital I had the Nikon D750. Not much, but overall about half a pound or .43 kilo. And the 24-105 lens on the front of the Sony is just enough shorter than the Nikon D750 with 24-120 to make it noticeable. So a win for the A7.
Conclusions – The eye auto focus is absolutely an outright advance for technology. It is easy to use and works well. This is a feature I expect to be standard on most cameras in a year or two. Mid day full sun shots on the other hand is a bit better than the Nikons but surprisingly not much better than on Sony’s low cost compact HX80. If the HX80 had been able to output raw I think it would be as good at mid day full sun shots as the A7. And then there is film. Film does not blow highlights easily like digital. But film needs to be developed and you normally want to use the full roll before developing it. But I will say that from what I know this is a win over the Nikon D5500. Back screen on the Sony is much faster than the Nikons. So I use it more. Too bad it is not touch like the D5500. Size is smaller with the A7iii over the D750 especially noticeable when using the kit lenses. Not so much with a prime 50mm.
If you the reader think I am struggling with my conclusions it is because I am. I have no struggle with eye auto focus. A great new feature. But for mid day full sun to me the Sony has proved to be better than the two older Nikon DSLRs but not reliably better than film. I have gone to some of my favorite places where I have shot photos over the last number of years and would say that Kodak Ektar gives a better average shot than the Sony. The back screen on the Sony moves just like a mirrorless should, fast. But certainly not as useful as a full touch screen. Then finally size. The Sony is smaller than the Nikon D750 but the D750 has a grip that fits my hand better. I do find the Sony and D750 with prime lenses about the same. The Sony is lighter but the Nikon is fine. But eye auto focus is a great feature to have. If I was going to be sent to a place where I could have only one interchangeable lens camera for a year I would be tempted to pick a Sony A7iii over a DSLR. Because it is great at both stills and video. But if I also had my iPhone XS Max along with me I would take the D750. Why. I think the D750 is more durable and less likely to break. The sensor is way back behind the mirror so I will be less likely to get buggered up. And at this point shooting video with an iPhone is more fun. And the results are fine.