|Full model name:||Sony Alpha ILCE-A7S|
|Viewfinder:||EVF / LCD|
|Dimensions:||5.0 x 3.7 x 1.9 in.|
(127 x 94 x 48 mm)
|Weight:||17.2 oz (489 g)|
|Full specs:||Sony A7S specifications|
Sony A7S Review -- First ImpressionsOverview and Technical Info by Dave Etchells and Mike Tomkins
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Rather than chasing ever more pixels, the Sony A7S takes a conscious step back, featuring an all-new 12.2-megapixel sensor with huge pixels -- by current standards, at least -- as well as some unique tweaks aimed at increasing dynamic range. The combination promises unprecedented low-light performance. By default, the Sony A7S has a sensitivity range of ISO 100 to 102,400 equivalents for still imaging or video. This range can be expanded for still shooting to encompass everything from ISO 50 to 409,600 equivalents in still shooting, and ISO 100 to 409,600 equivalents for video.
That's intriguing, but doesn't really tell us much about how it actually works. It sounds like the sensor itself is able to change the level of its output relative to photons received, rather than the system simply amplifying the signal once it gets off-chip -- but that's all just speculation on our part at this point. We'll try to get some more technical details on this shortly. In the meantime, we have learned from Sony that it expects a dynamic range of 15.3 stops from the A7S in raw format.
Another important feature for the A7S is the ability to use a Silent Shooting mode. Details from Sony are so far limited, but the rumor mill has it that this will allow fully-silent shooting with both electronic first and second-curtain functions, not simply a reduced noise level with electronic first-curtain and mechanical second-curtain, as in some competing cameras. If true, this is huge news for nature shooting, or any other environment in which silence is key.
No less important is the fact that the chip can output extremely high-quality, 16:9-aspect, 4K video without line-skipping, pixel binning or downsampling. It's not quite a native sensor readout, as there's still an approximate 1.1x focal length crop, but it's the closest to full-sensor width video we've yet seen from a full-frame imager. By contrast, Canon's EOS-1D C has a 1.3x focal length crop for 4K video, using only an APS-H sized area of the sensor.
The Sony A7S can't record 4K video directly, but can output an uncompressed 4:2:2 4K video feed via HDMI. You can use the same approach for Full HD video, or alternatively, opt for a choice of XAVC S or AVCHD codecs. Vanilla MP4 is also possible at 1,440 x 1,080 or below.
The A7S can record full HD video internally, though, and even offers a choice of AVC codecs. Beyond the standard AVCHD format, the Sony A7S also supports the XAVC S codec, previously found only in Sony's high-end Handycam professional camcorders. The XAVC S codec was designed to be able to accommodate 4K video, but in the case of the A7S provides high-bitrate full HD, at 50 Megabits/second.
The Sony A7S also supports what's known as S-Log2 gamma, a tone curve borrowed from Sony's pro video recorder line that greatly expands the practical dynamic range of its videos. This special gamma function applies a strong logarithmic tone curve to the sensor's output, rolling off the highlight end of the curve to preserve highlight detail. Viewed without a corresponding tonal expansion, the resulting video will look very flat, but the dynamic range is expanded over linear encoding by 1,300%, providing enormous dynamic range that can be exploited in post-production.
Other pro-level video functions include the ability to save "picture profiles", that include settings like gamma, black level and color adjustments. These settings can be shared across multiple A7S bodies, to ensure consistency in multi-camera shoots. The Sony A7S also provides time-code (free-run and rec-run), the ability to synchronize with external devices, marker and zebra displays on both the LCD screen and viewfinder, and can record dual XAVC S as well as MP4 simultaneously (MP4 at 1,280 x 720/30p).
Like the A7R, the Sony A7S lacks on-chip phase-detection autofocus elements, so it uses the same "Fast Intelligent AF" as the A7R, a system based solely on contrast detection. Sony promises better autofocus performance on the A7S, though, thanks to the larger pixels on its new sensor. In fact, for low-light autofocus it should best any phase detection system on the market, able to focus right down to light levels of -4EV, with an f/2.0 lens. (This is the lowest-light AF capability we've ever heard of, by a full EV step.)
|Differences between the Sony A7S, A7R and A7|
|Camera||Sony A7R||Sony A7S||Sony A7|
|Body-only List Price||US$2,300||US$2,500||US$1,700|
|Available in Kit with Lens||No||No||Yes|
|Body Materials||Magnesium alloy||Magnesium alloy||Magnesium alloy and polycarbonate|
|Sensor Size||35.9 x 24.0mm||35.8 x 23.9mm||35.8 x 23.9mm|
|Sensor Resolution (Total)||36.8 mpix||12.4 mpix||24.7 mpix|
|Sensor Resolution (Effective)||36.4 mpix||12.2 mpix||24.3 mpix|
|Maximum Image Size||7,360 x 4,912 pixels||4,240 x 2,832 pixels||6,000 x 4,000 pixels|
|Standard ISO sensitivity (Still)||100 - 25,600||100 - 102,400||100 - 25,600|
|Expanded ISO sensitivity (Still)||50 - 25,600||50 - 409,600||50 - 25,600|
|Standard ISO sensitivity (Video)||200 - 25,600||200 - 102,400||200 - 25,600|
|Expanded ISO sensitivity (Video)||N/A||200 - 409,600||N/A|
|Electronic First Curtain Shutter||No||Yes, optional||Yes, optional|
|On-chip Phase Detect Pixels?||No||No||Yes|
|Continuous Shooting Rate
(with continuous autofocus)
|1.5 fps max.||2.5 fps max.||2.5 fps max.|
|Speed Priority Continuous Shooting Rate||4.0 fps max.
(No Continuous AF)
|5.0 fps max.
(No continuous AF)
|5.0 fps max.
(Continuous AF supported)
|Autofocus Type||Contrast Detection
|Fast Hybrid AF
117-point (phase detect)
25-point (contrast detect)
|Predictive Autofocus Tracking||No||No||Yes|
|Flash Sync Speed||1/160 second||1/250 second||1/250 second|
|Maximum resolution for HDMI live view||1,920 x 1,080 pixels||3,840 x 2,160 pixels||1,920 x 1,080 pixels|
|Video codecs||AVCHD / MP4||XAVC S / AVCHD / MP4||AVCHD / MP4|
|Maximum clip length||29 min. (AVCHD); 20 min. / 2GB (MP4)||29 min. (XAVC S); 29 min. (AVCHD); 20 min. / 2GB (MP4)||29 min. (AVCHD); 20 min. / 2GB (MP4)|
|120fps at 720p?||No||Yes||No|
|S-Log 2 gamma option||No||Yes||No|
|Picture profile function||No||Yes||No|
|Maximum Magnification (Playback)||23.0x||13.3x||18.8x|
|Battery life (Still)||340 shots (LCD)
270 shots (EVF)
|380 shots (LCD)
320 shots (EVF)
|340 shots (LCD)
270 shots (EVF)
|Battery life (Video, clips with power-cycling and zoom)||60 min. (LCD); 65 min. (EVF)||60 min. (LCD); 55 min. (EVF)||65 min. (LCD); 60 min. (EVF)|
|Battery life (Video without power-cycling or zoom)||90 min. (EVF / LCD)||90 min. (EVF / LCD)||100 min. (EVF / LCD)|
|Weight (Body Only)||14.4 ounces (407g)||15.7 ounces (446g)||14.7 ounces (416g)|
|Weight (with battery and
Stick PRO Duo flash card)
|16.4 ounces (465g)||17.2 ounces (489g)||16.7 ounces (474g)|
CIPA-standard battery life for still shooting is rated at 380 shots per charge when using the rear-panel LCD, or 320 shots with the electronic viewfinder.
From all the above, it's clear that Sony had video recording -- and particularly 4K video recording -- firmly in mind when it developed the A7S. It'd be a mistake, though, to focus solely on that and assume that it's not a camera meant for still photographers as well.
The sensor's big pixels and special dynamic-range management capabilities mean it should provide unprecedented low-light capability for still shooters, too. And that's not to mention the possibility of very low noise levels when using high ISOs to freeze action under more moderate lighting as well.
Sony will be shipping the A7S in the US market from July 2014. And good news: Body-only list pricing is set at an impressively aggressive US$2,500! Suffice to say that we can't wait to get this camera in the lab for testing!
The Sony A7S is clearly aimed at videographers -- but it offers a whole lot that should prove very exciting to stills photographers, too!