Here is the latest Sony a7 IV review. According to DxOMark test results the Sony a7 IV (Amazon, B&H, Adorama) sensor gets a very high score of 97 points, with a combination of 25.4 bits color depth, 14.7 EV dynamic range, and 3379 ISO low-light score.
With a high score of 97 points, Sony A7 IV sensor wins the 7th position in the rankings for all sensor sizes, including medium format. That places the Sony A7 IV sensor performance alongside the older high-res full-frame sensors in the Nikon D810 and Sony Cyber-shot RX1R II compact, and just behind the Sony A1 and Sony A7R IV at 98 and 99 points, respectively.
Conclusion from DxOMark:
As the 24 MP BSI-CMOS full-frame sensor equips the out-going Sony A7 III, and the majority of Sony’s rivals at this level, the new 33 MP BSI-type CMOS in the Sony A7 IV will also probably appear in forthcoming competitor’s models, so the results are doubly interesting.
While the new sensor doesn’t perform a lot differently from the outgoing device, there has been a useful increase in the overall pixel count of 37.5% (albeit a 16.8% increase in linear pixel count on the long-edge). This may appear somewhat incremental, but when combined with the various improvements in stills and video features, the new Sony A7 IV is an incredibly well-rounded hybrid and a highly attractive option for all sorts of genres.