Image quality is extremely good, with excellent levels of detail, extensive dynamic range and attractive JPEG color. However, it's not significantly improved over its predecessor or its rivals: you'll get more detail in low ISO situations but this small gain seems to come with slight decreases in dynamic range and high ISO noise performance [...] Autofocus is powerful and can be very simple to use [...] Video is similarly impressive, with a host of tools [...]
I think that Sony has positioned itself for a cleaner market separation, as I found the release of the a7C muddied the waters a bit. The a7III and the a7C were too similar in terms of performance, and it was somewhat hard to choose between the two. The a7IV is a superior camera to the a7III and has a corresponding price at the $2500 mark [...] Sony has made some significant strides in improving some of their areas of weakness.