In June 2015, Sony Electronics announced record growth in sales of mirrorless cameras, a rapidly expanding segment of its interchangeable lens camera business. According to the NPD Group, overall mirrorless camera revenue had grown 16.5 percent over the prior 12 months (June 2014-15), while during the same time period, Sony stated a 66 percent increase in mirrorless camera sales.
In August 2015, Sony began shipping the Alpha a7R II, an updated model of the flagship in its line of full-frame mirrorless cameras. (We reviewed the a7R II positively in the October 2015 issue of Digital Video magazine.) Just after that, in October, Sony began shipping the a7S II, a refresh of the full-frame a7S that has been a favorite of both still and video users since it launched in 2014.
The a7S II adds significant value to the original a7S. While both cameras are built on the same full-frame imager, a 12.2 megapixel Exmor CMOS sensor, the a7S II adds in-body five-axis optical image stabilization, internal QFHD (3840 x 2160) recording up to 30 fps, 120 fps full HD 1080p recording, improvements to the electronic viewfinder, significantly faster auto-focus and 14-bit raw capture. Further, Sony beefed up the camera’s gamma curve options, adding S-Log3 to the already present S-Log2.
My first impressions of the a7S II are favorable for both still and video shooting. While the a7R II, with its 42.4 megapixel sensor, is targeted more at still photographers, the 12 megapixel resolution of the a7S II is more than adequate for professional still work. The internal QFHD movie recording in full-frame format features full pixel readout without pixel binning, delivering video with less moiré and jaggies.
The full-frame sensor coupled with fast lenses allows for an amazingly shallow depth of field. The camera is compatible with E mount lenses and a range of others via adapter.
Rolling shutter and aliasing are present in a7S II video but generally within acceptable tolerance. The use of a Super 35 lens or adapter (I use Metabones’ Canon EF Lens to Sony E Mount Smart Adapter Mark IV) switches the camera to a Super 35 sensor mode, which demonstrates some improvement in the inevitable effects of rolling shutter CMOS sensors.
The ability to shoot in either S-Log2 or S-Log3 makes the a7S II a bit more versatile than the a7R II, which is limited to S-Log2. Shooting the a7S II in S-Log3 4K XAVC S compared to the Sony PXW-FS7 in S-Log3, the a7S II image seemed a little more contrasty, even after application of Sony’s S-Log3 LC709A LUT, but I was able to get the footage to match perfectly in post. Sony is currently bundling the a7S II with its PMW-F5 camera, providing a complete A- and B-camera arrangement.
The camera’s native ISO is 1600, but it can practically see in the dark with a maximum ISO of 409600. Don’t expect a completely clean image at that speed, but the point here is that the a7S II is significantly faster than the a7R II—another reason why the a7S II might be more suitable for video. (The a7R II tops out at ISO 25600 for video recording.)
As mentioned, Sony improved auto-focus in this camera. The AF mechanism of the a7S II is a vast improvement over earlier models. Using a combination of the continuous auto-focus setting (AF-C), face detection and the camera’s five-point image stabilization, the camera did a very credible job following the movement of an individual as I shot handheld.
The XAVC S format supports QFHD recording at 30p or 24p frame rate with a maximum bit rate of 100 Mb/s. XAVC S files are minimized in size using Long GOP data compression and saved in the MPEG-4 AVC/H.264 format. The camera also records to a space-saving AVCHD codec at various bit rates. Note that the QFHD recording in the XAVC S codec is 8-bit with 4:2:0 sampling, while HD is 8-bit 4:2:2. HDMI output is 8-bit 4:2:2.
Because of heat and other considerations, continuous record is limited to 29 minutes and 50 seconds.
Just before the camera’s launch in October, Sony announced that the a7S II would feature compressed and uncompressed 14-bit raw image capture. The a7R II received the feature as well via firmware update.
Shooters who need a compact mirrorless camera for both still and video work should consider the a7S II seriously. Currently available, it is a stellar performer. Its list price is $2,999.99 (body only).