Review: Sony A7S

Review: Sony A7S

Introduction and features

Sony now has three full-frame compact system cameras to give photographers a choice depending upon what is most important to them.

Those wanting the ultimate in detail resolution should opt for the 36Mp Sony Alpha a7R, while photographers for whom low-light capability and video quality are of paramount importance should go for the 12Mp Sony Alpha a7S.

The middle ground is occupied by the 24Mp Sony Alpha a7, a camera that's capable of recording lots of detail, but has faster responses than the A7R.

Like t he A7 and A7R, the A7S has the Sony E-mount, but it's full-frame Exmor CMOS sensor has 12.2 million effective pixels. This is coupled with Sony's latest processing engine, Bionz X, which enables Sony's diffraction-reducing technology for better images at small apertures.

Sony's main focus for the A7S is its sensitivity range and noise control. We are told that the S stands for 'sensitivity mastered'. Consequently the A7S has a native sensitivity range of ISO 100-102,400, but this can be expanded for stills and video up to ISO 409,600.

That top figure is only currently matched by the Nikon D4S. The lowest setting can also be dropped down to the equivalent of ISO 50 for still images. The larger photosites (or pixels) should enable the camera to produce cleaner images at high sensitivity settings than a camera with greater pixel count.

I n addition, the Bionz X processor enables Sony's area-specific noise reduction, which analyses patterns, edges and textures to apply different levels of noise reduction with the aim of retaining fine detail but removing nose from areas of even tone (such blue skies).

Larger pixels should also bring wide dynamic range, the ability to record lots of tones in a single exposure. This is bolstered by the provision of Sony's Dynamic Range Optimisation (DRO) system and the ability to shoot HDR (high dynamic range) JPEG sequences that the camera merges together automatically.

Unlike the A7, there are no phase detection pixels on the A7S's sensor, and like the A7R it can only use contrast detection autofocusing. However, the larger photosites should also help here as the stronger signal that they generate in comparison with their 36Mp counterparts could give the A7S faster focusing in low light.

There's a healthy collection of AF point selection modes including Wid e, Zone, Centre, Flexible Spot, Lock-on AF: Wide, Lock-on AF: Zone, Lock-on AF: Centre, Lock-on AF: Flexible Spot with large, medium and small options for Flexible Spot mode. In addition, to single and continuous autofocusing, manual focusing is possible with focus peaking available to offer assistance.

Images may be saved as raw or JPEG files, or both simultaneously to an SD/SDHC/SDXC card or a variety of Sony Memory Stick options. The appearance of JPEG images can be adjusted using the 11 Creative Style options (Standard, Vivid, Neutral, Clear, Landscape and so on, each with customisable settings for contrast and the like) or the 13 Picture modes. Unlike the Picture modes, the Creative Style options may be used when shooting raw as well as JPEG images to obtain a 'clean' image for bespoke processing.

There are currently only fiv e full-frame Sony E-mount(FE) lenses available for the A7-series, but their focal lengths range from 24mm to 200mm. Sony APS-C format E-mount lenses can also be mounted, but on the A7S this is accompanied by a drop in image size to just 5Mp, something many photographers will consider unacceptable. Alternatively, mount adaptors are available for other full-frame lenses, so owners of Nikon or Canon full-frame lenses can use them.

Video features

Sony has also packed a lot of video technology into the A7S. For a start, it is able to record 4K video to an external device connected via an HDMI connection, which will make it attractive to enthusiast and professional videographers. The pro appeal is further bolstered by an audio level display that enables sound to be adjusted across 32 steps, Live (real-time) and Lip-sync settings and an optional XLR Adaptor kit to connect pro-end microphones via the camera's hotshoe.

There's also a stereo headphone jack for sou nd monitoring, a zebra view to indicate areas close to burning out and focus peaking to help with manual focusing. The A7S is also the first full-frame camera to feature full-pixel readout without pixel binning, which should give better image quality and more attractive bokeh.

When saving footage to a card, the camera is limited to shooting Full HD resolution (or lower) movies. Sony has made XAVC S format recording possible and this enables Full HD recording at 50Mbps for better image quality and reduced noise levels.

However, it's recommended that SDXC cards with higher than Class 10 performance are used when shooting XAVC S format footage. This recording format can also be used to shoot Full HD at 60p (50p), 30p (25p) or 24p â€" the higher figures are for recording NTS and those in brackets (PAL). AVCHD and MP4 format recording is also possible.

Another key feature is the ability to set Picture Profiles with specific values for Black Level, Gamma and Kn ee (highlight compression) as well as colour adjustment (Color Mode, Color Level, Color Phase and Color Depth) and Detail. The Gamma settings include Sony's S-Log2 setting which can increase dynamic range by up to 1300% to preserve highlight and shadow detail, and generate footage that is perfect for post-capture grading.

There's also Time code to help with scene identification and syncing footage from multiple cameras. In Record Run mode this only advances the time code while recording, but in Free Run mode it advances whether the camera is recording or not.

Build and handling

Full-frame cameras have shrunk considerably over recent years with the introduction of the Canon 6D and Nikon D610, but Sony's Alpha 7-s eries of compact system camera (CSC) sets a new benchmark for size.

Apart from a slightly more bulbous grip, the A7S (and A7 and A7R camera bodies) are very similar in size to the Olympus OM-D E-M5, which has a Micro Four Thirds sensor â€" smaller than the APS-C format devices in CSCs like the Fuji X-T1 and Samsung NX30.

Thanks to the fact that the top and front covers, as well as some internal sections are made from magnesium alloy, the A7S feels robust and solid in the hand. All the dials have a knurled edge to give them greater purchase and the small control buttons that sca tter the surface of the body have a fairly high-quality feel.

I found the textured front and rear grips of the A7S to be exceptionally comfortable and I was happy carrying the camera with the Sony 70-200mm f/4 attached without a strap for several hours. It felt secure in my grasp when taking shots as well as when walking around between shots.

There are two dials on the top-plate of the camera, the chunkier of the two is for setting the exposure mode and has options for program, aperture priority, shutter priority, manual, Automatic, Scene Selection, Sweep Panorama and movie along with two customisable options. The second is the exposure compensation dial and it has a range of +/-3EV marked in 1/3EV steps. Both dials have a high quality feel and allows quick adjustments to be made.

Although the exposure mode dial stayed wher e I had set it throughout this test, the compensation dial got knocked out of position a few times, so it's a good idea to keep an eye on it.

In manual exposure mode shutter speed is changed by rotating the rear control dial just below the top-plate, while aperture is adjusted via the front dial in the default arrangement, although this can be swapped if you prefer.

By default, the control wheel (which also doubles up as the navigation pad) on the back of the A7S is set to control sensitivity and it makes light work of scrolling from the automatic option, followed by the very lowest setting (ISO 50) all the way to the top value (ISO 409,600). The front and rear control dials, exposure compensation dial and control wheel allow exposure to be set very quickly and easily.

In its default arrangement the C1 (Custom 1) button on the top-plate is set to access the Focus Settings options, which include AF point selection mode. I found it better to change this to t he button at the centre of the control wheel/navigation pad so I could quickly press the centre button with my thumb and then use the surrounding navigation controls to select the point I need.

After the button has been pressed to access the Focus Settings, this also enables the surrounding control wheel to be used to select the AF point selection mode (Wide, Zone, Centre, Flexible Spot, Lock-on AF: Wide, Lock-on AF: Zone, Lock-on AF: Centre, Lock-on AF: Flexible Spot with large, medium and small options for Flexible Spot mode).

There's lots of scope for customising the A7S to suit the way you like to shoot as the majority of the controls and the Function menu can all be set to your preferences. It's worth spending some time with the camera in its default set-up and then gradually making changes until you find the optimum arrangement.

< /p>

Being a compact system camera rather than an SLR, the A7S has an electronic viewfinder (EVF). As on the A7 and A7R, this is a 1.3cm (0.5-inch) XGA OLED Tru-finder with 2,359,296 dots. It provides a superb and clear view with plenty of detail and colours, and exposure can be set to change as adjustments are made so that you usually know what you're going to get before you get it.

The 3-inch 921,600-dot tilting LCD also provides a clear view, but the 'Sunny weather' setting is a must in daylight on a UK summer's day even if the sun is behind a cloud. The tilting mechanism is useful if you're shooting landscape images from above or below head-height, but it's of no use for upright images. It's also sometimes a little hard to see the active AF point and the level as the screen is quite reflective.

Helpfully there's a sensor near the viewfinder that detects when the camera is held to the eye and activates the EVF. Although this worked satisfactorily during the m ajority of my testing, there was sometimes a slight delay in the view appearing in the finder.

Also, on a number of occasions the LCD screen refused to activate when the camera was taken away from my eye. There was nothing near the sensor so I cannot offer an explanation for this problem. It happened a few times and was usually resolved by turning the camera on and off again. Those who don't like the automated switching between the LCD and EVF can specify which they want to use.

Of course I can't pass up the opportunity to complain that the screen isn't touch-sensitive as this would speed up things, such a setting AF point and settings adjustments. Sony's Quick Navi Pro and Function menus would dovetail perfectly with touch-control, allowing fast settings selection and adjustment.

On the plus-side, it's pretty easy to set-up a Wi-Fi connection to your phone or tablet, especially if you have a NFC enabled device, and there's the Smart Remote Control PlayMem ory camera app that allows you to control the camera remotely.

Performance

While its lower pixel count means that the Alpha 7S can't resolve nearly as much detail as either the Alpha 7 or 7R, or the 16Mp Nikon D4S, images still look sharp straight from the camera and have enough detail to make high-quality A3 prints.

Noise is also controlled well and although I wouldn't recommend using ISO 409,600 unless you really have to, the results when shooting real-world scenes look a little better from the 12Mp A7S than they do from the Nikon D4S.

As we have seen from other recent Sony cameras, JPEGs have little in the way of chromatic noise even at high sensitivity settings. However, at 100% (actual pixels) on-screen there's a stippled texture that get's stronger as sensitivity increases. This may look alarming at 100%, but it manages to give the impression of detail at more common viewing sizes.

While it wouldn't be my first choice for shooting sport, it's clear that the A7S's AF system can lock onto and track moving subjects in good light.

In Lock-on AF: Flexible Spot mode it draws a box around what it believes to be the subject and then follows it across the frame. In most cases it appears to do a good job in decent light, but it can sometimes latch onto the wrong object and the size of the box sometimes makes it hard to see exactly where the system is focusing.

I found that the camera also manages to focus the lens automatically in low light conditions that challenge many other CSC's, but it is slower than a comparably priced SLR. That said, it doesn't tend to suffer badly from hunting until light levels get very low, or with close subjects.

When shooting video the autofocus adjusts smoothly and silently in decent light, producing high qualit y, sharp footage. However, as with stills, you need to take care with subjects close to the lens' minimum focusing distance as hunting can become an issue.

Images are generally well-exposed, but the brightness of the subject under the active AF point can skew the exposure a little when using the Multi-segment metering. I also found that the Alpha 7S isn't overly affected by bright areas within an image and this means that landscapes under bright skies usually look good. However, some scenes can be rendered a little too brightly and if you're shooting just JPEG files it pays to keep an eye on the highlights.

The exposure compensation facility can come in handy from time to time to avoid the brightest areas from being lost. Thanks to the high dynamic range of the A7S's raw files, it's often possible to bring back detail where it is lost in simultaneously captured JPEGs.

In the default 'Standard' Creative Style, JPEG images look very natural, although occasi onally they can look a little flat in comparison with the vibrant images from some other cameras, and may benefit from a slight boost to the saturation. Naturally, this won't be an issue for raw file shooters, but those who want a bit more punch direct from the camera can opt to use the 'Vivid' or 'Landscape' Creative Styles.

The automatic balance system also generally puts in a decent performance, but the results can be variable in shady conditions. On some occasions it makes the image look a bit too cool and the Daylight setting produces more attractive results, but on other occasions the exact opposite is true. Again, this is unlikely to be a major issue for experienced raw file shooters and videographers who are comfortable with grading footage.

We have found before that the A7-series of cameras tend to gobble through bat tery power and the A7S is the same. I found I was able to use the camera for around half a day (I turn the camera off between shots) and got in the region of 360 shots with simultaneous raw and JPEG file capture giving 720 files in total. This makes a second NP-FW50 battery essential for many users. Buyers in the US get a slightly better deal here as Sony bundle the camera with two batteries rather than just one, as in the UK and Australia.

Image quality and resolution

As part of our image quality testing for the Sony A7S review, we've shot our resolution chart. These images were captured using a full-production sample of the camera.

For a full explanation of what our resolution charts mean, and how to read them, check out our full explanation of our camera testing resolution charts.

Examining images of the chart taken at each sensitivity setting reveals the following resolution scores in line widths per picture height x100:

JPEG

ISO 50, Score: 22 (Click here to see the full resolution image)

ISO 100, Score: 22 (Click here to see the full resolution image)

ISO 200, Score: 22 (Click here to see the full resolution image)

ISO 400, Score: 22 (Click here to see the full resolution image)

ISO 800, Score: 20 (Click here to see the full resolution image)

ISO 1600, Score: 20 (Click here to see the full resolution image)

ISO 3200, Score: 20 (Click here to see the full resolution image)

ISO 6400, Score: 20 (Click here to see the full resolution image)

ISO 12800, Score: 20 (Click here to see the full resolution image)

ISO 25600, Score: 18 (Click here to see the full resolution image)

ISO 51200, Score: 16 (Click here to see the full resolution image)

ISO 102400, Score: 16 (Click here to see the full resolution image)

ISO 204800, Score: 14 (Click here to see the full resolution image)

ISO 409600, Score: 16 (Click here to see the full resolution image)

Raw

ISO 50, Score: 20 (Click here to see the full resolution image)

ISO 100, Score: 20 (Click here to see the full resolution image)

ISO 200, Score: 20 (Click here to see the full resolution image)

ISO 400, Score: 20 (Click here to see the full resolution image)

ISO 800, Score: 20 (Click here to see the full resolution image)

ISO 1600, Score: 20 (Click here to see the full resolution image)

ISO 3200, Score: 20 (Click here to see the full resolution image)

ISO 6400, Score: 20 (Click here to see the full resolution image)

ISO 12800, Score: 20 (Click here to see the full resolution image)

ISO 25600, Score: 20 (Click here to see the full resolution image)

ISO 51200, Score: 18 (Click here to see the full resolut ion image)

ISO 102400, Score: 18 (Click here to see the full resolution image)

ISO 204800, Score: 18 (Click here to see the full resolution image)

ISO 409600, Score: 18 (Click here to see the full resolution image)

Noise and dynamic range

We shoot a specially designed chart in carefully controlled conditions and the resulting images are analysed using DXO Analyzer software to generate the data to produce the graphs below.

A high signal to noise ratio (SNR) indicates a cleaner and better quality image.

For more more details on how to interpret our test data, check out our full explanation of our noise and dynamic range tests.

Here we compare the Sony Alpha 7S with the Sony Alpha a 7, Nikon D4S and Panasonic GH4.

JPEG signal to noise ratio

The Alpha 7S has the highest signal to noise ratio at its lowest and highest sensitivty settings, indicating that its images are cleaner than those from competing cameras - including the Nikon D4S.

Raw (after conversion to TIFF) signal to noise ratio

Although the Panasonic GH4 leads the way for the majority of its sensitivity range this doesn't extend as far ast the A7S's. At the very highest settings the A7S beats the Nikon D4S, but it's a pretty close run contest throughout the range.

JPEG dynamic range

All of the cameras capture a good dynamic range in their JPEG files but the Sony A7S appears to cope significantly better than the Nikon D4S at the higher vaules.

Raw (after conversion to TIFF) dynamic range

Again the Sony A7S beats the Nikon D4S at the higher sensitivity values, indicating that it can capture a wider range of tones in a single shot. The Panasonic GH4 does best its mid and high values though.

Sensitivity and noise images

JPEG

Full ISO 50 image, see the cropped (100%) versions below.

ISO 50 (Click here to see the full resolution image)

ISO 100 (Click here to see the full resolution image)

ISO 200 (Click here to see the full resolution image)

ISO 400 (Click here to see the full resolution image)

ISO 800 (Click here to see the full resolution image)

ISO 1600 (Click here to see the full resolution image)

ISO 3200 (Click here to see the full resolution image)

ISO 6400 (Click here to see the full resolution image)

ISO 12800 (Click here to see the full resolution image)

ISO 25600 (Click here to see the full resolution image)

ISO 51200 (Click here to see the full resolution image)

ISO 102400 (Click here to see the full resolution image)

ISO 204800 (Click here to see the full resolution image)

ISO 409600 (Click here to see the full resolution image)

Raw

ISO 50 (Click here to see the full resolution image)

ISO 100 (Click here to see the full resolution image)

ISO 200 (Click here to see the full resolution image)

ISO 400 (Click here to see the full resolution image)

ISO 800 (Click here to see the f ull resolution image)

ISO 1600 (Click here to see the full resolution image)

ISO 3200 (Click here to see the full resolution image)

ISO 6400 (Click here to see the full resolution image)

ISO 12800 (Click here to see the full resolution image)

ISO 25600 (Click here to see the full resolution image)

ISO 51200 (Click here to see the full resolution image)

ISO 102400 (Click here to see the full resolution image)

ISO 204800 (Click here to see the full resolution image)

ISO 409600 (Click here to see the full resolution image)

Sample Images

At normal print and viewing sizes details look nice and sharp in low sensitivity images, but they sometimes look a little over-sharpened at 100% on-screen. Click here to view full resolution image.

The A7S is responsive and fast when you spot a shot that needs to be taken quickly. Click here to view the full resolution image.

In good light the camera can produce sharp images of moving subjects. Click here to view the full resolution image.

Using the auto white balance setting produced warmer images than the Daylight setting here, but the reverse is true with other shots taken in shade. Click here to view the full resolution image.

The Daylight white balance setting produced a cool result here. Click here to view the full resolution image.

Colours look natural in the Standard Creative Style. Click here to view the full resolution image.

Detail has been retained reasonably well in this ISO 409,600 shot. Click here to view the full resolution image.

This image was captured using an E-mount lens designed for APS-C format. The A7S automatically crops to create a 5-million-pixel file. Click here to view the full resolution image.

The bright conditions have created slight underexposure here, but it's a good result and the highlights are retained. Click here to view the full resolution image.

The warm tones of the evening sun have been preserved by the Daylight white balance setting. Click here to view the full resolution image.

Verdict

Thanks to it relatively high price and low pixel count in comparison with the Sony A7 and Sony A7R, I think that the A7S is unlikely to prove hugely popular with enthusiast photographers. However, it could be very popular with enthusiast and professional videographers who want to build a rig around a small camera, and wedding photographers who will appreciate its low-light capability and rarely need to produce prints over A3 size.

These users will find the camera able to deliver high quality images and video footage in a wide range of situations. However, to really get the best from the A7S's video capability, it needs to be part of a system that includes an external recorder so that 4K footage can be saved. Users will also need to experiment with the range of video controls to create a look that they like, or one that's suitable for grading post-capture.

Th e A7S also benefits from having the same lens mount as the higher resolution A7 and A7R, which means that professional users who invest in the range can choose which model to use based on the shoots requirements â€" low-light capability (A7S), maximum detail resolution (A7R) or a more responsive al1-rounder (A7).

We like

Like the A7 and A7R, the A7S feels very comfortable in the hand and it's pleasant to carry and use over long periods of time. The degree of customisation that's available with the camera is also impressive and it allows users to optimise the controls for the way they like to shoot.

Videographers will also love the degree of control available via the Picture Profile options and will spend lots of timer tinkering to find the perfect set-up.

Image quality is also high, although it pays to shoot raw files to have the maximum flexibility with colour, brightness and dynamic range.

We dislike

My niggle with the LCD occasiona lly not activating after the camera was lowered from my eye is a concern; I was unable to find a specific cause or replicate the problem, it just happened on a few random occasions. If other users have a similar experience, we can hope for a firmware upgrade. It would be nice if the occasional slight delay to the EVF activating could also be rectified.

As we have said before, it would be nice if Sony could put a touch-sensitive screen on a camera higher up its CSC range. At the moment it sees this as something that's only of interest to more novice photographers. However, it can speed up making settings changes and setting AF point â€" although I'd want it in conjunction with the same degree of button and dial controls to allow flexibility in the way the camera is used.

It also a shame that the screen is a tilting device rather than a fully articulating unit, as this would be of much more use when shooting upright format images.

Our usual complaint that the Picture Effects can only be used in JPEG mode and not when shooting raw files is less of an issue with a camera that is aimed at videographers and pros who are more likely to apply effects post-capture. But I can't help mentioning it.

It would be nice if Sony UK and Australia could recognise that a second battery is pretty essential, as Sony USA seems to have done.

Verdict

Nikon told us for years that 12 million pixels was 'enough'. But as technology developed and commercial pressures came to bear, it increased the pixel count offered by its SLRs to the point that it introduced the first 36Mp full-frame SLR, the D800, recently replaced by the Nikon D810.

While the D800 is an excellent camera, capable of resolving a huge amount of detail at lower sensitivity settings, its users have to be prepared to follow all the 'rules' about using tripods, mirror lock-up and so on, to get the benefit from all of those pixels. In addition, they have huge files to deal with.

It's also interesting to remember that Nikon has stuck with a 16Mp sensor for its range-topping D4S and the retro-styled Nikon Df. This and the popularity of other 16Mp cameras like the Fuji X-T1, X-E2 and Olympus OM-D E-M1, E-M5 and E-M10 suggests that photographers now realise there's much more to a camera than its pixel count â€" and a high count can bring its own limitations.

So where does that leave the Song A7S? Well, it's an excellent camera, but still it's one that has limited appeal. The average enthusiast is usually less concerned about low light performance and high sensitivity settings than pros who have to shoot in gloomy conditions.

A professional wedding photographer, for example, might like it for its low light capability when shooting in churches and candle-lit receptions, but they are also likely to carry an A7 to enable them to take larger images (and therefore sell more expensive large prints) when shooting outdoors.

Videographers will also find it very appealing and a strong competitor for the Panasonic GH4, but one that allows greater control over depth of field thanks to its larger sensor.