The Sony Alpha 7 series became the first CSCs to feature a full frame sensor back in October 2013, and this new release brings 4K video and telephone-number ISO levels with it, becoming a serious option for DSLR / CSC film makers and those shooting in very poor light, as well as a direct rival to Panasonic's GH4.

One specification that instantly stands out is the drop to a 12.2 million pixel sensor. This drop in pixel count is likely to be in order to enhance video capture quality, but the new sensor enables a sensitivity range of ISO 200 to 409600 for movies and 50-409600 for stills.

Sony Alpha 7S
The sensor is full frame, with 12.2 megapixels

This maximum sensitivity of ISO 409600 for stills is the same as the recently released Nikon D4s, but with this CSC aimed at video makers rather than the D4s' stronghold of press photographers, it's going to be interesting to see what the quality for both images and video will be at this maximum value.

When it comes to video recording formats are all important, as they directly affect the quality of capture and flexibility of the camera in different environments.

The Alpha 7s features a range of recording formats that will appeal to professional video makers, including clean HDMI output for high quality and flexible 4K recording. This enables uncompressed video capture at 4K (QFHD; 3840 x 2160 pixels), with selectable 30p and 24p frame rates, which is then captured on an external video recorder.

When you still need to record in HD and without the ties of external recorders, the 7S is capable of using the XAVCs format, which enables Full HD recording at 50mbs to a memory card.

There are a host of other features that show that the 7S is a serious choice for video makers, including the S-Log2 gamma setting – common in commercial video equipment and no doubt a direct link to Sony's broadcast heritage. This enables better colour grading in post production by creating a wider dynamic range.

The sound capabilities, as with the 7R, include audio in and out as well monitoring.

We'll bring you more on the Alpha 7S soon.