Sony A7S Conclusion

Pro: Cons:
  • Outstanding high ISO performance, for both stills and video
  • Excellent JPEG¬†image quality at low to moderately high ISOs
  • Very good dynamic range
  • Picture Profiles including SLog2 for professional-grade dynamic range and picture customization for video and stills
  • XAVC S Full HD video is very high quality, with high bitrate
  • 4K video recording (see Con)
  • Uncompressed 8-bit 4:2:2 4K-resolution (Ultra HD 3840 x 2160) and 1080 HD via HDMI output
  • Able to autofocus in very low light (-4EV with an f/2 lens)
  • Fast single-shot AF speeds and very low shutter lag (with electronic first curtain shutter)
  • Up to 5 fps burst mode (but see related Con)
  • Very good buffer depths
  • Large, accurate viewfinder
  • Decent battery life for its class
  • Fast 1/250s flash sync speed
  • Silent Shooting mode (Is truly silent, but see related Con)
  • DRO helps with high contrast scenes
  • In-camera HDR works well
  • Useful Hand-held Twilight and Anti Motion Blur modes
  • Sweep Panorama Mode
  • 12 megapixels may not be enough resolution for some applications
  • 4K video recording is only available with external recorder (not recorded internally)
  • No Cinema 4K (4096 x 2160)
  • Very limited selection of native full-frame lenses
  • Sluggish startup time
  • Continuous AF not supported in 5 fps "Speed Priority" burst mode
  • Warm Auto white balance in incandescent light
  • Loud shutter
  • Silent Shooting mode reduces image quality (fully electronic shutter)
  • Single card slot (but supports SD or MS Pro Duo cards)
  • SDXC memory cards with 64GB capacity or larger required to enabled XAVC S format video
  • No built-in flash
  • Sweep Panorama can be finicky regarding subject matter or panning speed

With the A7S, Sony steered away from the megapixel race and offered a rather unique option for their customers: a large, full-frame sensor with only 12 megapixels. To create such a sensor, the individual pixels are made significantly larger than the pixels on, say, Sony's 24.3MP A7 and 36.6MP A7R cameras. Thanks to these larger pixels, the sensor is able to gather much more light per pixel, giving the Sony A7S outstanding high ISO and low-light performance.

In our tests and real-world shooting, the A7S lives up to its claim as a low-light shooting behemoth! For both still images and video, the Sony A7S can take photos in practically any lighting condition, even in near-complete darkness. Of course, with a maximum sensitivity going up to ISO 409,600, the A7S definitely produces noisy images at these extremely high ISOs, but nevertheless they are still able to show fine detail. Impressive. And it's not just the low-light image quality that's great, but the low-light autofocus performance has been significantly improved. The A7S can focus down to -4EV with an f/2 lens, compared to just 0EV with an f/2.8 lens on the A7.

While it may resemble a still camera, the Sony A7S is packed with a suite of professional-level video recording features. Among its video amenities, the A7S includes ultra-high resolution 4K video, higher bitrate Full HD, and Picture Profile support (borrowed from Sony's professional camcorder line) with SLog2 gamma for very wide dynamic range and increased latitude for post-processing.

The big story with the video front on the A7S is, of course, 4K video. With very high detail, excellent color and dynamic range, 4K footage from the A7S looks outstanding. The sensor is tailor-made for 4K with direct pixel readout using the full width of the sensor with no line skipping or pixel binning. That being said, there's a major downside in terms of convenience to shooting 4K with the A7S: you can't record it internally. To keep the slim, svelte design of the A7-series cameras, Sony opted to have 4K video capture available via HDMI out to an external recorder, since capturing 4K video on such a huge sensor would generate too much heat to record internally. The A7S is capable of streaming an uncompressed 8-bit 4:2:2 4K-resolution (Ultra HD 3840 x 2160) signal via HDMI.

This makes the A7S rather inconvenient for shooting spontaneous, casual 4K videos, as you'd always need to bring along an external capture device, some of which aren't designed to be very portable all. At the time of publishing this review, external 4K recorders are not only expensive but also hard to come by, with only a few options from companies like Blackmagic Designs and Atomos available. The target customer for the Sony A7S lean more towards advanced and professional-level shooters, so in this scenario if you're planning to shoot 4K for a full-on video production, the logistics of having external recorders isn't a major downside. Yet for more casual videographers, 4K video on the A7S is difficult.

Aside from 4K, however, the A7S offers higher quality, higher bitrate XAVC S video format for 1080p and 720p HD video, in addition to standard AVCHD and MP4 formats (though you'll need a 64GB or larger SDXC memory card in order to use this format). Image quality from internally-recorded HD video looks excellent, with great detail and dynamic range, even without using Picture Profile gamma adjustments.

Dynamic range, in both photos and video, is impressive. RAW files are very flexible to adjustments, especially to pull out detail in shadows areas. With Picture Profile enabled with SLog2, images becomes extremely flat -- necessitating some form of post-processing -- but you have tons of latitude to massage and adjust the footage in post-production.

In terms of other features, as well as physical and ergonomic qualities, the Sony A7S is nearly identical to its A7 and A7R brethren, with both good and bad qualities. The ergonomics are okay, but not great in terms of the placement of some controls and buttons. The newly-announced A7 II seems to have addressed practically all of our concerns with ergonomics, so perhaps this updated design will make its way into a future "Mark II" version of the A7S?

Also, by default, the shutter is still very loud, which is something we experienced with the other A7-series cameras. Thankfully, you can enable an electronic front curtain, or, on the A7S, use the completely quiet Silent Shooting mode to make snapping pictures much less noisy (unfortunately Silent Shooting mode does slightly degrade image quality).

Lastly, the selection of native FE lenses is still rather limited, but the E-mount is very adaptable for third-party lenses, providing great flexibility, especially for video shooters. The lens mount itself on the A7S is a little beefier than the two earlier A7 models (see comparison below. A7 and A7R are identical), with more of the flange construction comprised of metal for added durability.

All in all, the Sony A7S is a fantastic camera plain and simple, though pricier than the two earlier models. The unique, low-resolution-large-pixel full-frame sensor is capable of capturing stunning images in pretty much any lighting, with outstanding high ISO performance. At 12-megapixels, images are small enough for speedy editing and packing tons onto a single memory card, yet are still sufficiently high-resolution for all but the most demanding, large-format printing applications. For video recording, the A7S is equally impressive. With a sensor designed specifically for 4K video, UHD and Full HD footage is excellent, with great dynamic range, both for stills and video. 4K video is kind of a hassle to deal with, though, for casual shooters, but as part of a professional workflow, it fits in just fine.

If you want one of the best available-light cameras around with stunning high ISO performance, excellent Full HD and 4K video, all in a very compact design, the A7S is a top choice and an obvious Dave's Pick.

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