Sony launched the Xperia XZ in India in October last year. In April 2017, it launched the Xperia XZs, a phone that takes many visible cues from the Xperia XZ, but adds changes so drastic you would want to question the very existence of its predecessor. So much so, that you would want to question the very existence of the Xperia XZ in the first place.A lot of these changes that Sony has made have to do with the camera. It’s a pint-sized RX100 IV, the Xperia XZs. Just like the RX100 IV, Sony’s Xperia XZs can theoretically shoot slow-motion clips at a mind-boggling 960-frames-per-second. For your reference, the slowest slow-mos available in a commercially available phone right now can’t exceed 240 fps. Sony’s new phone can record videos 4X times slower than the slowest in the trade.Also Read: Sony Xperia XZs review: The pint-sized RX100 IV Understanding the super slow-mo tech inside the Xperia XZsThe Sony Xperia XZs uses a three-layer stacked CMOS sensor — as opposed to using a conventional two-layer sensor — that allows the system to accommodate a 128MB DRAM layer of memory in between the pixel section and the circuitry. It’s actually the DRAM layer that does all the heavy-duty stuff storing all the visual information the sensor takes in until it’s ready to be used by the rest of the phone, primarily the image processor. Since the system has been designed for speed Sony calls it Motion Eye.The 960 fps slow-motion mode is activated via a dedicated toggle inside the camera app. But if you thought freezing a live-action moment was as simple as pushing a toggle, well, it’s not that simple. Rather, it’s quite complex. For one, it’s going to take some time getting used to, and even when you do get used to it, recording a 960 fps slow-mo the way you imagined would be a hit or miss really. Timing and proper lighting are crucial.advertisement The Sony Xperia XZs uses a three-layer stacked CMOS sensor — as opposed to using a conventional two-layer sensor — that allows the system to accommodate a 128MB DRAM layer of memory in between the pixel section and the circuitry. It’s actually the DRAM layer that does all the heavy-duty stuff You can either record a regular video interrupted by short bursts of slow-mos or a full-scale slow-mo depending on the situation at hand. Since, 9 out of 10 times, your subject would be in some sort of motion you’ll have to be quick to make that decision.You begin by pushing the super slow-mo toggle that sits next to the standard video recording toggle. Once enabled, the process begins with a standard recording. You then wait for that perfect moment you want to freeze in time and push the same toggle again. The sensor would then capture a super slow-motion 960 fps video for a period of 0.182 seconds — only because that’s all the time it takes to fill up the 128MB DRAM layer of memory — before going standard again. Pushing the toggle once again would capture one more freeze-frame. So on and so forth. The recording — when played — would then play as standard video interrupted by 6 seconds of dramatic slow-mo depending on how many you recorded.It’s still early days for super slow-mo, in phonesWhile digital cameras can afford the luxury of protruding lenses, for a smartphone, to accommodate a similar sensor inside is no walk in the park. Even for a company like Sony that has literally spent eons supplying camera sensors to third-party OEMs. But, it’s still early days.The technology that Sony has employed inside the Xperia XZs is fantastic, but, it has its shortcomings.To begin with, you can record super slow-mos at mere 720p — even as the main camera can record 4K — and because it’s all a game of speed and accuracy, more often than not, focus would be an issue especially when shooting close ups. The farther the subject, the better the focus you would be getting in your videos. As for the video quality, well, a lot of it would depend on the available light. Since the sensor operates at a much higher ISO in super slow-mo, the quality of videos shot goes for a spin. Even more so in tricky and low light.Super slow-mo tech isn’t actually the Xperia XZs’ main USPThe Xperia XZs’ rear camera — Motion Eye — has a knack for moving objects. As soon as you fire up the camera app and should there be some sort of motion in view, the phone’s sensor is able to predict the same. The sensor then (predictively) captures three random shots of the object in motion before you actually press the shutter key. The focus is on getting the best possible — blur-free — result out of the given scenario. Once you’ve taken the picture, the camera app would show you four different cases of the same photo — three taken automatically by the sensor and one taken by you — and you can then chose to keep either all of them or select the best possible outcome.advertisementPredictive capture works by default in the Xperia XZs, which means that it is active all the time. The mode, however, springs into action only when it detects motion.But, is the Xperia XZs’ camera any good?The Xperia XZs sports a 19-megapixel camera on the rear — f/2.0 aperture — assisted with predictive phase detection and laser autofocus, but no Optical Image Stabilisation. There is EIS for videos though. But, more importantly, for the first time in a long time, Sony has favoured larger individual pixels — from 1.12um in last year’s Xperia XZ up to 1.22um in this year’s Xperia XZs — that should technically increase light sensitivity resulting in better low-light photos. The Xperia XZs is resultantly a better camera phone than the Xperia XZ.Photos clicked with the XZs come out well in good lighting. The phone is able to hold and retain plausible dynamic range with little or no metering issues like the Xperia XZ before it. The Xperia XZs photos are less susceptible to digital noise even in tricky light, a problem that was a major point of concern in the Xperia XZ.Low-light is where the Xperia XZs makes a strong case for itself over the Xperia XZ. Low-light photos shot with the phone have more detail and far less noise in comparison.The post-processing algorithm on-board is still marred by a slight delay in processing and saving pictures after you’ve clicked them though. Even more so during predictive capture.The Xperia XZs is a better all-round performer than the Xperia XZThe Xperia XZs is powered by a quad-core Qualcomm Snapdragon 820 processor (clocked at 2.15GHz) coupled with 4 gigs of RAM and 64GB of internal memory which is further expandable by up to 256GB via a microSD card slot. The Xperia XZ, meanwhile, came with the same Snapdragon 820 processor but with 3 gigs of RAM.The dual-SIM Xperia XZs runs Android 7.1.1 Nougat-based Xperia UI and supports 4G LTE (VoLTE-ready). Sony has been able to well optimise the software with the hardware in the phone. It actually feels much faster and more fluid than last year’s Marshmallow-based Xperia XZ. It does have a slight tendency to get warm occasionally, and gets a little too hot especially while playing graphical games for longer periods or while recording 4K or streaming 1080p videos. It is also fairly quick to cool down.Another point to note is that the Xperia XZs has far less bloat or unwanted apps in comparison to the Xperia XZ.advertisementAnd now the similarities– The Xperia XZs, like the Xperia XZ, comes with what Sony calls loop surface design. It’s an all-metal smartphone with razor sharp — even to the extent of being uncomfortable for some — edges and side-mounted deep-seated — even to the extent of being uncomfortable for some — fingerprint scanner. It is IP68-certified for dust and water resistance which is nice and uses USB Type-C for charging and data syncing. High-res audio via compatible headphones is also supported by the Xperia XZs.– The Xperia XZs comes with a 5.2 Full-HD 1080p display which feels like an AMOLED panel in actual usage, with its near over-saturated colours, high contrast ratio and pleasantly sharp viewing angles. Colours are often not the most accurate, something which is more pronounced when you switch alternatively between Sony’s custom user interface and the Chrome browser for instance. There’s an option to manually correct colour temperature — which works just fine — in case you’re not impressed.– The Xperia XZs, much like the Xperia XZ, boasts of front-firing stereo speakers which get really loud and punchy with little or no distortion at peak volume. It’s again one area where the phone really stands out.– Phone calls made with the phone are of excellent quality and we did not encounter any odd call drop issues with our review unit. The phone supports dual-SIM, 4G LTE (VoLTE-ready), USB Type-C (v 2.0) and NFC connectivity options.– The Xperia XZs, like the Xperia XZ, is also backed by a 2,900 mAh battery. Battery life is good. In our battery benchmark, we subjected the device to an hour of 1080p video playback, half an hour of GPU-intensive gaming, 45 minutes of basic games, phone calls (to the tune of one hour), some music streaming and YouTube video playback along with web browsing, and we were able to get almost 14 hours out of the device. Not the best, but, no slouch either. Still, Sony could have upped the battery capacity to maybe a 3,000mAh this time round.A combination of old and new makes Xperia XZs a better packageOn the one side, the Xperia XZs has future-proof camera hardware, on the other it comes with a dated design, a 1080p screen, dated processor and a too small for comfort battery. But, in the case of the Xperia XZs, the combination of dated design, a 1080p screen, dated processor and a too small for comfort battery actually works in its favour. The Xperia XZs is a way better phone than the Xperia XZ and a lot of it has to do with the fact that it’s a much better optimised phone than its predecessor. Its futuristic camera hardware is just the icing on the cake.For a long-term Sony phone, the Xperia XZs is definitely a recommended buy. It’s not too bad for the others as well.Also Read: Sony Xperia XZ review: Being good isn’t good enough anymore