The latest arrival in Sony's Alpha series comes with a host of bells, whistles and functions, not least of which is 4K video. We run through nine important things you need to know

Images/video: Sony

1. Want to shoot 4K video on the Alpha 7s? You’ll need an external recorder

‘4K video’ was the phrase on the tips of everyone’s tongues from the moment the Sony Alpha 7s was announced.

However, something that was only lightly touched upon in the promo material, and left out of much of the coverage altogether, was the fact that you can’t record 4K video with just a Sony Alpha 7s.

Unlike with the Panasonic GH4, which uses the new UHS I class III SD card format to save data at 30 MB/s, recording 4K footage with the Sony Alpha 7s requires hooking up a third-party external recording device via HDMI – that’s the only way you’ll get the kind of data gathering capability that 4K requires.

2. It’s the first CSC, and second digital camera, to shoot at ISO 409,600…

Nikon and Sony must be ready to spit blood and teeth at each other. The Nikon D4s‘s reign as the only camera to shoot at ISO 409,600 lasted barely a month before the Alpha 7s came bursting through the door after it, shooting at the exact same ISO.

Image: Nikon

3. … and what’s more, ISO 409,600 looks surprisingly good

It’s pretty common for a camera’s highest ISO settings to be essentially unusable, and naturally you wouldn’t expect an ISO as high as 409,600 to be any different.

Sony released a pretty beautiful video showing off the Alpha 7s’s full ISO range, and what’s remarkable is how, well, not awful the highest ISO settings look. See for yourself

4. The 12.2MP Exmor sensor can read the entire pixel array without pixel binning

The brand new 12.2MP CMOS sensor on the Alpha 7s is (currently) the only full-frame sensor around that can read the entire width of the pixel array for video without pixel binning  – which means combining data from a group of pixels into a single pixel.

This unique capability is how the camera is able to capture such high quality video, without moiré or false color artifacts.

5. It can shoot video in super slow-motion

High frame-rate shooting of 120 frames per second at standard HD resolution allows for, Sony says, a 5x slow-motion effect. Perfect for sports, fast action, or mocking people’s facial expressions.

6. The S-log2 Gamma setting boosts dynamic range in video by 1300%

Sony’s promotional material promises that activating this proprietary Sony gamma setting will create a whopping 1300% wider dynamic range in video, for smoother gradation and reduced blackout and whiteout. With post-production colour grading, you can enhance the detail even further.

7. The autofocus system is entirely contrast based…

While the Alpha 7 made a show of sporting on-sensor phase detection AF, it remains the only camera in the family to do so, with the Alpha 7s sticking with tried-and-tested contrast-detect AF.

Although we don’t yet know for certain, it’s likely to be very similar to the contrast-detect AF system we saw on the Alpha 7R. if that’s the case, we shouldn’t have anything to worry about.

8. … and it can perform well in exceptionally low light.

Sony promises that the Fast intelligent AF will be able to function in extremely poor lighting conditions (-4 EV, ISO 200 with f/2 lens). Combined with the advanced ISO capability, this should make the camera a serious low light contender.

9. And finally, the ‘s’ stands for…

‘Sensitivity’.

There, that clears that up.