Sony A7S II vs A7 II vs A7R II: which should you buy?

November 2, 2015Matt Golowczynski

Unsure whether the Sony A7s II or A7 II or A7R II is right for you? Our in-depth comparison will help you decide…

It’s been seven years since the first compact system camera arrived on the market, but Sony stands alone in offering models equipped with full-frame sensors designed to tempt professionals away from similarly specified DSLRs.

The only other current full-frame alternative is Leica’s M-series of rangefinders, although being decidedly more niche and vastly more expensive means they can’t realistically be considered in the same way as mainstream offerings.

The company has recently refreshed its initial full-frame A7, A7R and A7S trio with second-generation models of each, each designed with different intentions. So which one should you buy? Read on to find out all the main differences between the three.

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Sony A7S II vs A7 II vs A7R II: Sensor Size

Although each of the three cameras uses a slightly different sensor to the others, each one is classed as full frame. This means they apply no crop factor to any of the E-Mount lenses designed for the system, although only Sony’s full-frame ‘FE’ lenses will make use of the camera’s full sensor resolution.

Despite this commonality, scrutinising each camera’s spec sheet reveals they all marginally differ in size from one another.

At 35.6 x 23.8mm, the sensor inside the a7S II is the smallest, followed by the inside the 35.8 x 23.9mm unit inside the A7 II, and finally the a7R II’s 35.9 x 24.0mm sensor – although this shouldn’t make any practical difference.

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Sony A7S II vs A7 II vs A7R II: Sensor resolution and sensitivity

While the sensors are all roughly the same size, each camera goes down a different path when it comes to pixel count and sensitivity. The A7S II offers the same sensor as its predecessor, with a modest pixel count of 12.2MP, while the A7 II also continues with the same 24.3MP device as in the A7. The A7R II stands on top of the pack, with an effective pixel count of 42.4MP.

Theoretically, this means the A7R II should not only be able to resolve details that rival high-resolution, full frame cameras from other systems, but it should also bother some medium format models too.

Sony also claims the sensor inside the camera is the world’s first full frame, back-illuminated sensor, with the architecture promising higher resolution, sensitivity and readout speeds compared with conventional front-illuminated types.

The sensitivity crown, however, goes to the A7S II; with a relatively restrained pixel count, its already impressive native sensitivity range of ISO 100-102,400 can be expanded to settings equivalent to ISO 50 and 409,600 (when capturing still images) for shooting in all manner of lighting conditions.

The other two don’t fare badly here, though, both being able to capture images across a standard range of ISO 100-25,600. The A7 II’s range is expandable to ISO 50-51,200 equivalents and the A7R II improves on this slightly with ISO 50-102,400 equivalent settings.

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Sony A7S II vs A7 II vs A7R II: Autofocus

The A7S II is the only camera out of the trio not to offer a Hybrid AF system – ie one that marries phase-detection autofocus with contrast-detection autofocus for speedy acquisition.

Instead, it offers a 169-point contrast-detect AF system, although with sensitivity being the camera’s focus, it comes as no surprise that it can focus down to -4EV. This represents a benefit of two stops over the systems inside the A7R II, and three stops over the A7 II’s.

The A7 II and A7R II each offer 25 contrast-detect AF points, and these are paired with 99 phase-detect AF points on the former and a staggering 399 phase-detect points on the latter to form each camera’s Hybrid AF system.

Sony goes on to claim that the A7R II’s system is 40% faster at acquiring focus than the one inside the A7R, while the A7 II manages a lower – but still respectable – 30% speed boost over the one inside the previous A7.

The A7S II, meanwhile, is also said to have had its AF speed doubled over the previous A7S when shooting videos.

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Sony A7S II vs A7 II vs A7R II: Design and build quality

All three models are styled very similarly to one another, each sporting a mottled finish around non-rubberised areas and a magnesium alloy construction that’s sealed against dust and moisture.

The trio are decidedly more substantial than their predecessors, and have had their grips redesigned, two things that should make them easier to hold and operate, particularly with longer lenses.

The change in design has also necessitated a repositioning of the shutter release button and front command dial on each, and the A7 II has had its previously tall rear command dial redesigned to be as thin and tactile as those on its siblings.

A further change is that it’s the only model out of the three not to have a locking button in the centre of its mode dial, meaning it can be turned freely at all times.

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Sony A7S II vs A7 II vs A7R II: Stability

With each camera being heavier than the one it replaces, the three are likely to be more stable in the hand, which in turn should enable sharper images.

Further helping here, the three share the same 5-axis SteadyShot INSIDE system, which sees corrections applied to roll, pitch and yaw, together with vertical and horizontal shifting.

Sony promises this provides a compensatory effect of up to 4.5EV stops for each, although exactly what you can achieve here will depends on the lens you use and your technique.

The A7R II and A7S II also employ a shutter mechanism that Sony claims produces 50% less vibration than the original models, which should help with image sharpness too.

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Sony A7S II vs A7 II vs A7R II: Battery life and continuous shooting

On a full charge of the battery, Sony reckons the A7s II will marginally outlast its siblings, quoting 370 frames when the LCD screen is used and 310 if you opt for the camera’s electronic viewfinder instead.

The A7 II isn’t too far behind, with up to 350 frames using the display and 270 with the viewfinder, while the A7R II drops to just 340 using the screen and but a slightly better 290 using the finder.

Just how fast your battery drains, however, depends on a range of other factors such as how frequently your image stabilisation system is employed and exactly which other features you have activated.

Both the A7 II and A7R II can be programmed to fire consecutive frames at a rate of 5fps, with AF maintained throughout the burst, and while the A7S II’s standard rate is only half this at 2.5fps, this can be boosted to 5fps in the Speed Priority Continuous mode, with AF fixed to reading from the first image.

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Sony A7S II vs A7 II vs A7R II: Video

All three cameras are capable of recording full HD videos in a choice of frame rates up to 60fps, and all can have their footage output via clean (uncompressed) HDMI. The A7R II and A7S II, however, bolster this with 4K video capture in camera, which records at a higher QFHD resolution of 3840 x 2160 at up to 30fps on each model.

Not only that, but the pair record 4K video using the full sensor – ie without pixel binning – to boost clarity and minimise aliasing artefacts, while the A7R II goes on to offer a Super 35mm crop mode which only uses the central portion of the sensor but still outputs 4K footage.

The A7R II and A7S II can also be programmed to record at up to 120fps for slow-motion footage, with the A7R II capturing this at 720p and the A7S II managing to do the same at the full HD 1080p resolution, and all the three models employ the XAVC S codec; this allows full HD recording at 50Mbps on all three and 4K recording on the A7R II and A7S II at 100Mbps.

While all three support the same S-Log2 Gamma setting for enhanced dynamic range, the A7S II also adds S-Log3 for better tonal reproduction from shadow to mid tones.

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Sony A7S II vs A7 II vs A7R II: Price and conclusion

While the A7S II and A7R II command hefty body-only asking prices of £2500 and £2600 respectively, the A7 II manages to offer its compelling mix of features for around £1250.

So, you could get the A7 II with the well-regarded Sony FE 24-70mm f4 ZA OSS Vario-Tessar Carl Zeiss T* Lens and it would still come in cheaper than one of the other bodies alone.

This is partly explained by the high-resolution, backside-illuminated sensor inside the A7R II and the A7S II’s unique proposition of a full-frame camera that can capture 4K footage in very poor lighting conditions.

With the pricier two being more niche, and the fact that a number of cameras are believed to share the A7 II’s 24.3MP sensor, economies of scale are no doubt also also a factor.

So which do you go for? Well, aside from how flush you’re feeling, it depends on exactly what you need it for.

The A7 II is a tempting and relatively affordable proposition for anyone stepping up from APS-C systems or crossing over from full-frame DSLRs, and so for many, this will be the one to go for – regardless of the genre in which they shoot.

For plenty of flexibility when shooting in low light and high-quality video, the A7 S II is the answer, but for studio and landscape photographers, and anyone else for whom detail is key, the A7R II appears hard to beat.

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