Sony broke ground in the camera world in 2013 with the announcement of the A7 line of cameras — the first mirrorless cameras with full-frame sensors. They were exceptional cameras, even with a handful of notable flaws. Then, last year, the company announced a more video-minded version with the A7s, which could shoot 4K video and had truly unbelievable low light performance. Now, Sony is building on that with the brand new A7s II.

The first new feature you notice about the A7s II is 5-axis image stabilization. Sony made waves when it added 5-axis stabilization to the A7 II back in November, making it the first full-frame camera with such a feature. But it makes even more sense here, considering how powerful the A7s II should be when shooting in low light. Last year Sony said the stabilization added 4.5 stops of exposure compensation to the A7 II, and there's no reason to expect it would be any different here.

Speaking of that, the A7s II has the same, astronomical ISO range of 50 to 409,600 as its predecessor. But Sony says that the camera's image processor has been upgraded with a new algorithm that should make it even more capable in low light, particularly at "the mid-high end of the ISO scale." Any bump in performance would be significant, because the original A7s already offered jaw-dropping performance at high ISOs — just look at this video that was shot in nothing but moonlight:

As much as Sony's A7 and A7r cameras are aimed at photographers, the A7s line is made for videographers, and so the company has made some other improvements to the A7s II that will please minds obsessed with moving pictures. The camera can shoot 4K video at a higher bitrate than before, 100 Mbps, and now it can capture that footage internally. (Users of the original A7s needed an external recording device to capture 4K footage.) Sony also says the camera can capture this 4K footage without any "pixel binning," which is when an image sensor combines the information captured by neighboring pixels to reduce noise, resulting in a slight sacrifice in quality. The A7s II can also record slow motion 1080p footage at 120 frames per second, which is five times slower than normal speed.

Other improvements have been made to the A7s II, like an upgrade to the autofocus system that increases the AF point count to 169. Sony promises that not only will the autofocusing in the A7s II work better in low light — something that is always a challenge, regardless of who makes the camera — and it will be two times faster in video mode than the original A7s.

The camera's electronic viewfinder has also been upgraded, and the camera's grip and shutter buttons have a new design as well. Improvements like these are always welcome, but it's hard to tell how significant they are without a real world test.

The rest of the camera has stayed more or less the same. The 35mm-sized full-frame sensor still captures 12.2 megapixels. There's a tilting LCD screen on the back of the camera for lining up shots with it at your hip or over your head. The A7s II is also Wi-Fi and NFC-enabled, and you can control it with Sony's (pedestrian) PlayMemories mobile app. News about upgrades to the mediocre battery performance — one of the biggest sticking points with all of the A7 cameras — is conspicuously absent from the press release, but you should expect it to last about 350 shots.

Sony says the new A7s II will be available in October for "about $3,000" in the US. The company also says that it will add seven new full-frame lenses to its lineup by early 2016, which means owners of the A7s II (and the rest of the A7 line) will have 20 native lenses to pick from.