While the A9 records beautiful quality 4K video, it actually isn’t as videographyorientated as the A7R III, which has a lot of the extra functions demanded by professional film-makers. For starters, there’s the option of recording 4K video full frame with no pixel-binning, but there’s also a ‘Super 35’ format which records at 5K resolution and then downsamples to 4K, which further enhances the image quality. The ‘Super 35’ format introduces a focal length magnification factor of 1.5x (i.e. the same as ‘APS-C’), but the extra quality will make this a small price to pay for some users. Better still, switching between the formats is now quick and easy.
The A7R III records 4K video in the Ultra HD resolution of 3840x2160 pixels (Ultra HD) and at 25 fps or 24 fps with two quality settings which represent bit rates of 100 or 60 Mbps. Full HD clips can be recorded at 100 fps (PAL) for smoother slow-motion effects – as it’s up to five times overspeed – as well as at 50, 25 or 24 fps. Both the PAL and NTSC standard frame rates are available and, via the ‘S&Q’ mode (Slow & Quick Motion), a range of frame rates from 100 fps down to 1.0 fps can selected along with the record rate (i.e. 24, 25 or 50 fps) to record slow or quick motion clips. As usual, Sony prioritises the high-bit-rate XAVC S format with MPEG-4/H.264 AVC compression, but AVCHD is available for Full HD recording. S-Log 2 and S-Log 3 profiles are now both supported to make the most of the extended dynamic range, but as the processing is still 8-bit (and not 10-bit), Sony’s S-Gamut colour can still end up looking a bit strange (especially skin tones). Far more useful is the new Hybrid Gamma Log (HGL) profile based on the new BT.2020 colour space, which is a new 4K HDR TV standard. Consequently, the HLG profile enables a much easier workflow for output to HDR displays which, of course, is more and more the case these days. Curiously, Sony is offering four HLG profiles on the A7R III and, at this stage, it’s not clear what the differences are. For straight out-of-the-camera colour and contrast variations, there are ten video-centric ‘Picture Profiles’, while the refined ‘Creative Style’ presets are also available.
As with the A9, the A7R III records 4K video both to the memory card with 8-bit 4:2:0 colour and also to the HDMI output with 4:2:2 8-bit colour at 24 or 25 fps. A ‘clean’ 2K output is also available at 24 or 50 fps with 8-bit YCbCr 4:2:2 colour. The dual card slots allow for simultaneous recording of video clips to both (but at all the same settings, so it’s for making a back-up rather than anything else). There’s a dedicated video start/stop button on the back panel, but the shutter release can also be set to this function. There’s also time-coding, zebra patterns, gamma display assist and a focus peaking display.
Stereo microphones are built-in, with adjustable levels and supplemented by both a stereo audio input and an output. These are standard 3.5 mm minijack connectors, but the ‘Multi Interface Shoe’ supports various dedicated Sony accessories such as an external microphone or video light. An XLR adaptor module is also available and provides two balanced mic inputs.
Video functionality includes all the PASM exposure control modes, the ‘Picture Effects’ and continuous autofocusing with tracking, which is where the limited touchscreen functions are most effective, enabling quick and, more importantly quiet, point selection with smoother pull focusing. Again, the AF performance is outstanding, especially the reliable tracking of fast-moving subjects when shooting FHD footage. The sensitivity range for video is ISO 100 to 32,000 and the camera’s high ISO performance is much improved over the A7R II with great-looking footage even at ISO 12,800 (and with full frame 4K as well as the ‘Super 35’ format).
While there will inevitably be a Mark III update of the more videoorientated A7S at some point (and with 10-bit colour to match Panasonic’s GH5/ GH5S models), the A7R III is a very capable video camera with all the benefits of the mirrorless configuration combined with a 42.4 MP full-35mm sensor, superb autofocusing and low light performances, effective image stabilisation, better in-camera colour and longer battery life. What’s not to like?