Sony Announces Third Alpha A7 Model… With 4K Video
With its original Alpha 7 full-35mm CSCs still making waves around the world, Sony has announced a third model which is primarily aimed at videographers, but will also appeal to ‘purist’ photographers. The new Alpha 7S (full title the Alpha ILCE-A7S) – which joins the existing 7 and 7R variants – has the same compact bodyshell as its siblings and also a full-35mm size ‘Exmor’ CMOS sensor, but this imager has a total pixel count of 12.4 million (12.2 MP effective). While this is half the resolution of the A7 and one-third that of the A7R, there’s method in Sony’s madness as the very big pixels deliver exceptional low light performance. The native sensitivity range is equivalent to ISO 100 to 102,400 with expansion to ISO 50 to 409,600 for stills and ISO 200 to 409,600 for video recording.
Additionally, Sony says the A7S employs a newly developed on-sensor technology which enables optimisation of the dynamic range across the full ISO 50 to 409,600 sensitivity range. Additionally, this on-sensor technology is said to broaden the range of tonal gradation in bright environments while also minimising noise in dark scenes “…allowing the camera to deliver impressive results in these extreme conditions where other cameras typically struggle”. The sensor also delivers significant benefits when shooting video. For starters, it’s the first with a full pixel read-out during video shooting (i.e. without pixel binning or down sampling) which, in conjunction with the new high-speed ‘Bionz X’ processor, allows the A7S to process data from all the sensor’s pixels and output exceptional quality Full HD and 4K video (the latter being QFHD quality at 3840x2160 pixels) while utilising the full-width of the sensor. The read-out of all pixels frees the video footage from aliasing, moiré and false colour artefacts while, of course, lenses maintain close to their marked focal lengths (especially important with wide-angles) as the magnification factor is only 1.1x. Additionally, the A7S camera is equipped with S-Log2 gamma which is inherited from Sony’s professional video cameras, S-Log2 expands the dynamic range by up to 1300 percent to minimise clipped highlights and loss of detail in shadows.
The Alpha 7S records 4K video to an external recorder via an uncompressed (8-bit, 4:2:2 colour) feed to its HDMI connector. Full HD video is recorded either to the memory card or via the HDMI output and there’s the option of using the workflow-friendly XAVC S recording format in addition to the more common AVCHD and MP4 codecs. XAVC S format allows for Full HD recording at a data rate of 50 Mbps with lower compression for broadcast quality.
Other pro video functions include a picture profile that adjusts settings like gamma, black, level and colour adjustment; and can be saved for use in a multi-camera shoot. The Alpha 7S has the same ‘Multi-Terminal Interface Shoe’ as its siblings which is compatible with Sony’s XLR Adaptor Microphone Kit (currently the XLR-K1M, but a new one is on the way), allowing the use of pro-level microphone systems.
The rest of the feature set is similar to those of the A7 or A7R, but like the latter, the A7S has solely a contrast-detection AF system (rather than a hybrid arrangement)… presumably because many videographers will be focusing manually anyway.
Local pricing and availability for the Alpha 7S has yet to be announced, but for more information about the camera itself visit www.sony.com.au