Bramansde compiled two interesting videos showing off the high ISO capabilities of the Sony a99II while shooting photos and video. You can download his RAW, JPEG and video files here. If you would like to see ever more samples Andreas Peters did a comparison between the a77II, a7II, and a99II. They can be found here. At this time there are very mixed opinions about the Sony a99II’s high ISO performance that range from astonishing to just below the Sony a7RII. From what I have seen it seems to be just below the Sony a7RII, but only because of the translucent mirror that provides it with it’s unique autofocus capabilities.
Sony a99 Mark II B&H Photo/Amazon/Adorama
Via Petapixel