Sony Cyber-shot RX100 IV review: Sony RX100 IV: Small camera, big video
The Sony Cyber-shot RX100 IV (M4) is less of an clear upgraade over its predecessor the RX100 III (M3) than a forked alternative; for a variety of reasons, I'd classify it as an advanced compact for video enthusiasts rather than a straight-up advanced compact, at least until the price drops a bit. Though it's more expensive and adds a plethora of video capabilities, it's pretty much delivers the same photo quality in the same body.
A nice choice if you're looking for an advanced compact with class-leading video capabilities, the Sony Cyber-shot DSC-RX100 IV is a little expensive if you just want a good camera for shooting stills.
Great video features to supplement its 4K capabilities distinguish the Sony Cyber-shot RX100 IV from the rest of the advanced-compact pack. It also retains the nice design perks, like a popup electronic viewfinder, of the earlier RX100 models.
Like its predecessor, the autofocus system could be more consistent and the battery life has gotten even worse.