The a7S is the third model in Sony's full-frame mirrorless lineup, a 12MP camera that puts as much emphasis on its movie capture capabilities as its still image prowess. While the a7S is a capable still shooter, Sony has emphasized that its real focus (no pun intended) is videography.
The first thing you need to know about the a7S is that it can record 1080p footage internally or be used to output 4K video to an external recorder. The internal 1080p footage is recorded using the XAVC S format, a more consumer-friendly version of Sony's XAVC system. This is the first of the company's cameras to use the format, which frees the camera from the bitrate restrictions of the AVCHD standard.
However, while the a7S's body exactly resembles its original 24 and 36MP sister models, the a7 and a7R (the a7 II's design is slightly different), it includes a whole raft of features and tools to support the videographer. These include the low contrast S-Log2 tone curve that allows more of the camera's dynamic range to be fitted into its video files and the option to record time code. Photographers more interested in stills may wish to note that most of these video features have subsequently been included in the newer a7 II, which also features revised ergonomics and in-body image stabilization.
Key Features
- 12MP full-frame EXMOR CMOS sensor
- Focuses at light levels to -4EV
- 1080 footage at up to 50Mbps (XAVC S)
- Extensive movie-focused capture options: S-Log2, Black Level, time code
- Video ISO Range 100 - 409,600
- Uncompressed 4:2:2 Full HD and 4K video output over HDMI
- 2.36M dot OLED viewfinder
- Mic and headphone sockets
- 720/120p option for slow-mo capture
- Wi-Fi with NFC
For the most part, however, modern DSLRs and mirroless cameras don't offer much support for their video features. The technical capability is there, but even on cameras where a decent level of manual control is provided, tools such as focus peaking and zebra patterhsn that have been standard on dedicated video cameras for many years are often missing. This extends even to cameras such as the Canon 5D Mark II and Nikon D800, whose respective manufacturers are happy to promote video features despite the fact that support for actually using video is somewhat lacking. Canon has subsequently upped its game with the EOS 5D Mark III and the lessons it's learning from the development of its Cinema EOS line, but in general video is promoted much better than it's supported.
The Sony a7S steps around these pitfalls, offering both focus peaking and zebra highlight warnings to help videographers get footage that lives up to the cameras' capture capabilities (you can, however, purchase external monitors that can show the same information on other cameras). They also have add-on accessories available to allow use of industry-standard audio or video connections.
Another shortcoming of many 'HDSLR's is that they capture the relatively low resolutions of video by only sampling 'stripes' of their sensors - a process that's become known as line-skipping. This leads to lower vertical resolution in the video, along with a greater risk of moiré. The a7S avoids this by reading out its entire sensor thirty times per second. And, because its sensor appears to have been designed with video in mind, it's able to intelligently downscale this output into cleaner, more detailed video.
However, just because they go to unusual lengths to accommodate the videographer, this doesn't mean any compromises have been made to the feature sets they offer the stills shooter. Noticeably, the Sony offers the same handling and controls as its more stills orientated a7 and a7R models.
Here's how the a7S sits in Sony's a7 lineup:
| Sony a7S | Sony a7 II | Sony a7R | ||
|---|---|---|---|---|
| Sensor specifications | 12MP full-frame | 24MP full-frame | 36MP full-frame | |
| Video formats | XAVC S, AVCHD, MP4 | XAVC S, AVCHD, MP4 | XAVC S, AVCHD | |
| Highest bitrate | 50Mbps (1080p) | 50Mbps (1080p) | 28Mbps (1080p) | |
| ISO Range (Stills) Standard / Expanded |
100 - 102,400 50 - 409,600 |
100 - 25,600 50 - 25,600 |
100 - 25,600 50 - 25,600 |
|
| ISO Range (Movies) | 200 - 102,400 200 - 409,600 |
200 - 25,600 | 200 - 25,600 | |
| Image Stabilization | In-lens only | In-body | In-lens only | |
| S-Log2 picture profile | Yes | Yes | No | |
| Electronic first curtain shutter | Yes | Yes | No | |
| Battery life (CIPA) | 360 | 350 | 340 | |
| Weight | 489g | 559g | 465g |
Sony a7S specifications
| Price | |
|---|---|
| MSRP | $2499 |
| Body type | |
| Body type | SLR-style mirrorless |
| Body material | Magnesium alloy |
| Sensor | |
| Max resolution | 4240 x 2832 |
| Other resolutions | 4240 x 2384, 2768 x 1848, 2768 x 1560, 2128 x 1416, 2128 x 1200, 1376 x 920, 1376 x 776 |
| Image ratio w:h | 3:2, 16:9 |
| Effective pixels | 12 megapixels |
| Sensor photo detectors | 12 megapixels |
| Sensor size | Full frame (35.8 x 23.9 mm) |
| Sensor type | CMOS |
| Processor | Bionz X |
| Color space | sRGB, AdobeRGB |
| Color filter array | Primary color filter |
| Image | |
| ISO | Auto, 100-102400 |
| Boosted ISO (minimum) | 50 |
| White balance presets | 10 |
| Custom white balance | Yes |
| Image stabilization | No |
| Uncompressed format | RAW |
| JPEG quality levels | Extra fine, fine, standard |
| File format |
|
| Image parameters |
|
| Optics & Focus | |
| Autofocus |
|
| Autofocus assist lamp | Yes |
| Digital zoom | Yes (2x) |
| Manual focus | Yes |
| Number of focus points | 25 |
| Lens mount | Sony E (NEX) |
| Focal length multiplier | 1× |
| Screen / viewfinder | |
| Articulated LCD | Tilting |
| Screen size | 3″ |
| Screen dots | 921,000 |
| Touch screen | No |
| Screen type | TFT-LCD |
| Live view | Yes |
| Viewfinder type | Electronic |
| Viewfinder coverage | 100% |
| Viewfinder magnification | 0.71× |
| Viewfinder resolution | 2,400,000 |
| Photography features | |
| Minimum shutter speed | 30 sec |
| Maximum shutter speed | 1/8000 sec |
| Exposure modes |
|
| Scene modes |
|
| Built-in flash | No |
| External flash | Yes (via Multi Interface shoe) |
| Flash X sync speed | 1/250 sec |
| Drive modes |
|
| Continuous drive | 5.0 fps |
| Self-timer | Yes (2 or 10 sec; continuous (3 or 5 exposures)) |
| Metering modes |
|
| Exposure compensation | ±5 (at 1/3 EV, 1/2 EV steps) |
| AE Bracketing | ±5 (3, 5 frames at 1/3 EV, 1/2 EV, 2/3 EV, 1 EV, 2 EV steps) |
| WB Bracketing | Yes |
| Videography features | |
| Resolutions | XAVC S 1080/60p(50Mbps), 30p (50Mbps), 24p (50Mbps). 720 120p (50Mbps). AVCHD 60p (28Mbps), 60i (24Mbps/17Mbps), 24p (24Mbps/17Mbps) |
| Format | MPEG-4, AVCHD, XAVC S |
| Videography notes | XLR support via adapter |
| Microphone | Stereo |
| Speaker | Mono |
| Storage | |
| Storage types | SD/SDHC/SDXC, Memory Stick Duo/Pro Duo/Pro-HG Duo |
| Connectivity | |
| USB | USB 2.0 (480 Mbit/sec) |
| HDMI | Yes (micro-HDMI port with 4:2:2 8-bit 4K or 1080 video output) |
| Microphone port | Yes |
| Headphone port | Yes |
| Wireless | Built-In |
| Wireless notes | with NFC and wireless control via smartphone |
| Remote control | Yes (wired) |
| Physical | |
| Environmentally sealed | Yes |
| Battery | Battery Pack |
| Battery description | NP-FW50 lithium-ion battery and charger |
| Battery Life (CIPA) | 380 |
| Weight (inc. batteries) | 489 g (1.08 lb / 17.25 oz) |
| Dimensions | 127 x 94 x 48 mm (5 x 3.7 x 1.89″) |
| Other features | |
| Orientation sensor | Yes |
| Timelapse recording | No |
| GPS | None |
Body, Operation, and Controls The camera has two main dials that emerge from the top plate, as well as the familiar rear dial that doubles as a four-way controller. The main dials always handle exposure: program shift in P mode and aperture and/or shutter speed in the others. The rear dial can have up to five settings assigned to it, though that can be dangerous, as accidentally turning said dial is very easy. There are two ways around this: simply assign nothing to the rear dial, or turn on the lock function which requires a button-press before it can adjust anything.
This means that, despite our reservations about the menu system, overall the a7S is a pleasure to shoot with. The camera is responsive, focuses quickly in good light (but not-so-well in low light), and the LCD and EVF have no noticeable lag. While a touchscreen like the one found on the Panasonic GH4 would've been nice, it by no means hurts the shooting experience. Here are the options which can be placed into the Fn menu:
Auto ISOThe Sony A7S has the same auto ISO implementation seen in its A7-series siblings, which essentially means it's not as sophisticated as the programmable auto ISO algorithms offered for years in Nikon DSLRs, and more recently in Canon DSLRs. This means you can't tell the camera the minimum shutter speed it should allow for before upping the ISO to increase image brightness. The camera automatically selects this minimum shutter speed and, furthermore, it's not very clever - in Aperture Priority, for example, 1/60s is always chosen, regardless of the lens' focal length or optical stabilization capabilities. It's particularly egregious that one can't bias this automatically selected shutter speed, given its unsophisticated behavior.The silver lining here is that the A7S does offer auto ISO in M(anual) mode, which means you can work around the lack of programmable auto ISO by switching to M mode, dialing in the appropriate shutter speed and aperture, and then allowing the camera to automatically select the appropriate ISO to achieve proper image brightness. To lighten or darken the image relative to this 'proper' image brightness, one can use the exposure compensation dial. That is, exposure compensation continues to be available in M mode with auto ISO - an addition to most modern high-end cameras that we're quite pleased to see. Video controlsAs mentioned earlier, Sony made no changes to the control layout between the a7/a7R and the a7S. The front and rear control dials that you use for adjusting exposure are fine for stills, but when shooting video the microphone will pick up the clicking sound when their rotated.Something else that hasn't changed is the placement of the video recording button. After receiving negative feedback about the placement of this button on the NEX-7, Sony has been moving it further and further away, in order to prevent users from accidentally pressing it. The problem now is that it's too far away - essentially on the right side of the camera - and it's so flush to the body that you may have to hunt for it.
Video can be recorded in any shooting mode, or you can select to only use the dedicated movie mode position on the mode dial. Its main advantage is that it previews the correct framing instead of having to switch when the 'red button' is pressed as in other shooting modes. You can still switch between P/A/S/M mode via the Fn. menu. Regardless of what mode you're in, exposure, focus mode, and ISO sensitivity can all be adjusted while you're recording. Focus peaking and zebra can also be turned on and off. Exposure is adjusted using one or both of the control dials, which you can configure to your liking. The a7S allows you to shoot in manual exposure mode with Auto ISO, which keeps the aperture and shutter speed consistent. Even in Auto ISO mode, brightness can be adjusted using the exposure comp dial on the top plate. This makes it possible to set the shutter speed and aperture and let the camera worry about maintaining the brightness. Other settings can be changed via the Function menu while recording, though that can distract from your workflow. Functions you want to quickly turn on and off, such as zebra, can be assigned to one of the custom buttons. | ||||||||||||||||||||||
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Sony Alpha 7S Samples GalleryThere are 36 images in the preview samples gallery. Please do not reproduce any of these images on a website or any newsletter / magazine without prior permission (see our copyright page). We make the originals available for private users to download to their own machines for personal examination or printing (in conjunction with this review), we do so in good faith, please don't abuse it.Unless otherwise noted images taken with no particular settings at full resolution. Because our review images are now hosted on the 'galleries' section of dpreview.com, you can enjoy all of the new galleries functionality when browsing these samples. Sony Alpha 7S samples gallery
36 images • Posted on Jul 31, 2014 • View album
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