Sony A7s vs A7R vs A7? If you're in the market for a full-frame, mirrorless compact system camera, the Sony A7 range has to be top of your hitlist. But which A7 model is right for you: Sony A7s or A7R or A7? Marcus Hawkins takes a look at the three contenders in our Sony A7 comparison.
The Sony A7s, Sony's new full-frame E-mount compact system camera, sits at the top of the flagship 'expert' line of Alpha models.
A highly-specified camera that offers full-frame 4K video shooting capabilities and high-sensitivity shooting at ISO 409,600, the Sony A7s is a tempting prospect for digital film-makers as well as photographers who need a camera that can essentially see in the dark.
The A7s release date and price have yet to be confirmed, but it shares much in common with the already-available Sony A7 and A7R, including a BIONZ X image processor, a full-frame Exmor CMOS sensor and the same compact camera body.
SEE MORE: Sony A7 / A7R review
The Sony A7s lacks the ultra-high resolution of the A7R and the hybrid phase detection/contrast detection autofocus system of the A7, but it introduces a newly developed sensor that offers a similar sensitivity range to the Nikon D4s.
So is the Sony A7s the best camera for your needs, or should you consider either the A7R or the A7 instead? Do you need 4K video or is Full HD more than enough?
Is the ability to shoot handheld in low light important or are do you always shoot with a tripod and need high resolution images instead?
Hopefully, this Sony A7s vs A7R vs A7 comparison will highlight the key differences that will make your buying decision easier…
Sony A7s vs A7R vs A7 comparison: 01 Sensor resolution and ISO
At 12.1MP, the Sony A7s's newly-developed CMOS sensor has the lowest resolution of the three cameras. The Sony A7 offers twice the resolution at 24.3MP, while the A7R's sensor packs in 36.4MP - the same as the Nikon D800.
With the trend for high-resolution full-frame sensors, the A7s seems a step backwards. After all, Nikon's previous generation FX-format DSLRs - the Nikon D700 and Nikon D3 - both offered the same 12.1MP resolution.
However, with fewer, larger pixels on the Exmor CMOS sensor, the Sony A7s offers the potential for an improved signal-to-noise ratio, and as a result should deliver a better low-light performance.
The A7s offers a native ISO sensitivity range of ISO 100-102,400 for stills (expandable to ISO 50-409,600), and ISO 200-102,400 for movies (expandable to ISO 200-409,600).
In comparison, the A7R offers a native ISO range of ISO 100-6,400 for stills, which can be boosted to give a low ISO of 50 and high ISO of 25,600.
The 's' in A7s stands for 'sensitivity', and for good reason: it offers a native ISO performance that's 4 stops better than the A7R.
How often you're likely to need - or be desperate enough to use - the maximum ISO of 409,600 is debatable though.
Banish bad pictures: 9 quick fixes for common camera complaints
44 essential digital camera tips and tricks
10 ways to drive a photography snob mad
10 common exposure problems every photographer faces (and how to overcome them)
Sony A7s vs A7R vs A7 comparison: 02 Video
Aside from ISO performance, the other key difference between the Sony A7s and its Alpha stablemates comes in the shape of the A7s's advanced video capabilities.
The Sony A7 and A7R both offer Full HD video (AVHCD progressive, 1920x1080p @60p), but the A7s also brings 8-bit 4:2:2 4K video capture, stealing a march on other DSLR and Compact System Camera manufacturers, aside from Panasonic - a company which, like Sony, has an enviable heritage in the professional camcorder business.
Aimed squarely at commercial videographers, the A7s is capable of 'Clean HDMI' output at 4K (3840x2160) resolution, meaning that uncompressed footage can be recorded to a 4K-compatible recorder attached to the camera, or displayed on a compatible monitor or TV.
In fact, 4K has to be recorded to an external device - only HD footage can be saved internally.
A superimposed time code when Clean HDMI is selected, with Record Run (for advancing the time code only while recording) and Free Run (which advances the timecode at all times), and both drop frame and non-drop frame options available.
The A7s offers a wider range of recording frame rates, including 4K at 30p/24p and Full HD at 50p/25p, as well as a slow-motion standard HD resolution (1280x720) option - although you'll need to switch from full-frame to the cropped APS-C mode to enable it.
In slow-motion mode, the A7s burns through footage at 120fps. Played back at 24p, this gives a speed that's 5x slower than normal.
What's more, Sony claims that the sensor in the A7s is the first full-frame one in the world to be capable of full-pixel read-out without pixel binning when shooting video.
'Binning' is a process whereby groups of pixels essentially act as a single pixel, reducing the effects of noise with the trade-off being a reduction in resolution.
The A7s doesn't let any information go to waste - data is taken from every pixel - although this only counts when movies are being recorded at 24p/30p(25p).
In addition to recording footage in the Sony-and-Panasonic-developed AVHCD Progressive format, the Sony A7s introduces the XAVC S format to the Alpha camera range.
This enables higher-quality Full HD recording at an increased bitrate of 50mbs, although Sony recommends using an SDXC memory card of Class 10 or higher when shooting movies in this format.
A new Dual Record function debuts on the Sony A7s too, enabling the camera to capture a 720p stream alongside the higher 50mbs XAVC S footage.
To improve dynamic range and make it easier to bring out detail, the A7s uses Sony's proprietary S-Log2 gamma setting.
The S-Log2 curve is designed to produce a dynamic range that's 1,300% wider than standard gamma, reducing the chances of burned-out whites and clipped blacks.
Footage might look flat straight out of the camera, but this improves the colour grading possibilities during post-production.
You can also apply your own distinctive look to movie footage before you shoot, by adjusting gradation, colour tone and intensity and other effects, and then saving this mix as a Picture Profile (the A7s has seven such profile slots available).
Needless to say, the video functions of the Sony A7 and A7R don't come close to those in the A7s.
10 reasons why your photos aren't sharp (and how to fix them)
9 secrets to using a tripod like a pro
The best shutter speeds for every situation
Best camera focus techniques: 10 surefire ways to get sharp photos
Sony A7s vs A7R vs A7 comparison: 03 Design and build quality
In terms of design, the 's' slots neatly into the A7 line-up - it shares the same button layout, magnesium alloy chasis and small proportions - 126.9mm x 94.4mm x 48.2mm - as the other two cameras.
As a result, the A7s can also lay claim to being the world's smallest interchangeable-lens digital camera with a full-frame sensor.
At 446g body only, the Sony A7s is a heavier camera though - the A7 weighs 416g, while the A7R is lighter still at 407g.
Like the A7/R, the A7s includes a headphone jack for audio monitoring during movie recording and playback, as well as built-in stereo microphones.
It also features a 2.4 million dot XGA OLED electronic viewfinder and a tiltable 3" LCD - essential for comfortable movie shooting - although the lack of touchscreen on such a video-centric camera may ultimately prove frustrating.
PAGE 1 - Sony A7s vs A7R vs A7 comparison: Sensor resolution, ISO; Video; Design
PAGE 2 - Sony A7s vs A7R vs A7 comparison: Continuous shooting, battery life; AF, metering; Price
PAGE 3 - Sony A7s vs A7R vs A7 comparison: our conclusion
10 killer photography tips the pros won't tell you
First camera crash course: simple solutions for mastering your new DSLR
Crop photos the right way: classic mistakes and how to avoid them
Flash photography tips: external flash techniques anyone can understand