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Sony Motion Eye camera explained, or how the Xperia XZ Premium shoots epic slow-motion videos

Sony Motion Eye camera explained, or how the Xperia XZ Premium shoots epic slow-motion videos

Remember the bullet time special effects introduced by the Matrix movie? Remember the action scenes of Neo caught in a mid-air battle against the evil, all-powerful agent Smith? Man, those were epic! Such stunts required some serious gear to pull off, and even though it has been two decades since then, I doubt that a modern smartphone would be enough to reproduce them. But perhaps there's a couple of phones that could get close.

At this year's Mobile World Congress, Sony introduced the Xperia XZ Premium and Xperia XZs, both of which feature a brand new camera that can perform some nifty tricks. Their Motion Eye camera, as Sony calls it, shoots dramatic slow-motion videos – four times slower than any other phone on the market – and can capture photos of moments in time before the shutter is pressed. Impressive, right? But how does this fancy new camera work? Well, that's what we're going to explain in the paragraphs below. 

How is slow-motion video made?


Back in 2015, Sony announced the fourth generation of its RX-100 compact digital camera – a camera that did not go unnoticed by photography enthusiasts. It could shoot stills at a rapid rate, video at a whopping 4K resolution, and – perhaps most impressively – slow-motion clips at a mind-boggling 960 frames per second (fps). To this day, the slowest slow-mos out of a commercially available phone do not exceed 240 fps.

Now, I better put these figures into context in case it's not entirely clear what they mean. In a nutshell, video is little more than a sequence of images/frames that change fast enough to create the illusion of motion. Traditionally, movies are shot at 24 frames per second, with some exceptions like Avatar or The Hobbit shot at 48 fps. The great majority of YouTube videos are streamed at 25 or 30 fps. 

But here's where the magic happens: if you play a video at the rate at which it was recorded (e. g. playing a regular 30fps video out of a phone at 30 frames per second) it would appear to run at a normal speed. A higher framerate would make motion in the video look a bit smoother and more realistic (possibly giving you a mild feeling of dizziness along the way), and that's pretty much it. However, if you play video at a framerate lower than the original, that would create a slow-motion effect. For example, playing a 960fps video at 30fps would make objects appear as if they're moving 32 times slower than in real life. Here's what that looks like:


How is this technically possible?


That was a cool video, right? Sony's RX-100 camera was able to achieve the said framerate because it had an image sensor designed for speed. You see, shooting at 960 frames per second generates tons of data over a short period of time, so to mange that data effectively, a special DRAM memory element was built into the sensor. That DRAM acted as a buffer, storing the visual information until it was ready to be handled by the image processor. 

Unsurprisingly, the Sony Motion Eye camera in the Xperia XZ Premium and Xperia XZs is built on the same principle, only applied on a smaller scale to make the module fit into a smartphone. The image sensor in use consists of three layers: a pixel section at the top, circuitry at the back, and a DRAM element sandwiched between them. 

A Conventional 2-layer stacked CMOS image sensor (left) vs the new 3-layer stacked CMOS image sensor. DRAM element shown in orange

A Conventional 2-layer stacked CMOS image sensor (left) vs the new 3-layer stacked CMOS image sensor. DRAM element shown in orange


So, how do you shoot Super Slow-motion video on the Xperia XZ Premium and XZs?


It's quite the process, actually, but you should be able to get the hang of it after a few practice turns. Two things you will absolutely need, however, are good timing and plenty of light.

As seen in the picture below (and in the video, at the 1:14 mark), 960fps videos are accessed from the video camera screen. Above the record button, there's a smaller button that makes Super Slow-motion accessible. But even after pressing it, you're still not recording anything. You have to hit thе record button to start taking regular video, and then pressing the button a second time enables Super Slow-motion 960fps video for a period of 0.182 seconds (or about a fifth of a second). This is then transformed into 6 seconds of dramatic, Super Slow-motion video. Pressing the button again will capture another 0.182-second portion at 960fps.

That small button above the big one activates Super Slow-motion videos on the Sony Motion Eye camera

That small button above the big one activates Super Slow-motion videos on the Sony Motion Eye camera


Again, timing is of importance here, as you have to hit the Super Slow-motion button at the right time to slow down that special moment. Of course, it would have been much more convenient if we could manually select the portion of the video that is to be slowed down, but alas, that's not technically feasible. As we mentioned above, 960fps slow-mos are buffered in the camera's DRAM, and that, despite being 128 megabytes in size, gets filled up in under 2 seconds. Another downside of Super Slow-motion videos is that image quality is greatly reduced due to the increased sensitivity (ISO) of the camera. You'll need plenty of light to capture good-looking 960fps slow-mos. 

For the record the Sony Motion Eye camera can shoot 120fps videos to which you can later add slow-motion effects for a specific portion of the footage.



What about that "taking photos before the shutter is pressed" part?


Ah yes, super slow-motion movies aren't all that Sony's Motion Eye camera has to shine with, and in fact, this feature is looking a lot more practical. Long story short, the cam starts taking photos automatically if it detects motion in the frame (hence the Motion Eye naming of the camera). Once you press the shutter, you're given not only the picture that you took, but also three other full-resolution frames that were captured a few moments earlier.

To be clear, there's nothing that you have to do in order to activate these special Motion Eye abilities. Designed with user friendliness in mind, the feature is integrated seamlessly into Sony's Intelligent Auto mode (set by default), so there's no need to fiddle with modes or settings. Of course, you do get a cue letting you know that the camera used its special abilities – a little "Predicted" notification pops up in the corner of the camera UI.


But what about image quality? Are regular photos any better?


That's an excellent question. Up until now, Sony's smartphone cameras were characterized with having big sensors with lots of megapixels, but with relatively small individual pixels. Smaller pixels make a camera more susceptible to digital noise (that fuzzy distortion you see when you zoom in) and less sensitive to light, which is likely one of the reasons why the 23MP Sony Xperia XZ struggled against the 12MP iPhone 7 in a recent camera comparison

The Sony Motion Eye camera makes a shift to a lower number of megapixels – from 23MP down to 19.3MP – and larger individual pixels – from 1.12um up to 1.22um. As a result, we're expecting to see superior image quality compared to last years' Xperia models, especially in low light. And yes, we will do a camera comparison to confirm whether or not that's the case, but until then, the gallery with images below is all we can provide. Friendly reminder: the Sony Xperia XZs unit used to take the images was a pre-production unit.

Full resolution images out of the Sony Motion Eye camera
Full resolution images out of the Sony Motion Eye camera
Full resolution images out of the Sony Motion Eye camera
Full resolution images out of the Sony Motion Eye camera
Full resolution images out of the Sony Motion Eye camera
Full resolution images out of the Sony Motion Eye camera

Full resolution images out of the Sony Motion Eye camera

Xperia XZ
Xperia XZs
Xperia XZ Xperia XZs
iPhone 7 Plus
Xperia XZs
iPhone 7 Plus Xperia XZs

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Related phones

Xperia XZ Premium
  • Display 5.5" 2160 x 3840 pixels
  • Camera 19 MP / 13 MP front
  • Processor Qualcomm Snapdragon 835, Octa-core, 2450 MHz
  • Storage 64 GB + microSDXC
  • Battery 3230 mAh(24.7h 3G talk time)
Xperia XZs
  • Display 5.2" 1080 x 1920 pixels
  • Camera 19 MP / 13 MP front
  • Processor Qualcomm Snapdragon 820, Quad-core, 2200 MHz
  • Storage 32 GB + microSDXC
  • Battery 2900 mAh

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27 Comments

maherk

Posts: 6427; Member since: Feb 10, 2012

Can you comment on the focus speed?

jellmoo

Posts: 2514; Member since: Oct 31, 2011

This. Focus and capture speed is seldom flagged in camera articles, and I find it to be one of the most important parts of whether or not I enjoy the camera experience.

maherk

Posts: 6427; Member since: Feb 10, 2012

It pisses me off when they leave such an important aspect in a camera lens out of these tests. Not everyone just want still shots, I for example prioritize focus speed because most of the pictures I take are of kids.

jellmoo

Posts: 2514; Member since: Oct 31, 2011

It's the same for me and my dogs. The best picture composure and scene accuracy in the world does nothing for me if I can't focus and capture before the moment is over.

Nick_T

Posts: 182; Member since: May 27, 2011

Guys, we should be able to produce more in-depth testing of the camera in about 2-3 weeks. The units at MWC were pre-production ones, which is why we intentionally avoid commenting on certain aspects until the right time comes. But thanks for commenting, and I'll keep your request in mind.

jellmoo

Posts: 2514; Member since: Oct 31, 2011

For me, it's kess about this specific example (since I imagine access was limited to the device) and more a general principle moving forward. We see lots of camera comparisons and review, but focus and shutter speed seldom gets more attention than a throwaway line at best.

cireyaj15

Posts: 41; Member since: Jan 06, 2014

Right. I have been asking the minimum shutter speed it can set. No one seems to answer it yet.

maherk

Posts: 6427; Member since: Feb 10, 2012

I am talking in general Nick, rare are the reviewers who compare focus speeds in their tests, the only one I can think about is SuperSaf. I hope you guys start highlighting more on this area. People with kids and pets see this aspect as a great deal when it comes to photography.

Chuck007

Posts: 1407; Member since: Mar 02, 2014

High five @ fellow dog lover. I too find it a priority cause I often take pics of my dog.

Shamoy

Posts: 112; Member since: Dec 28, 2013

Has laser autofocus, extremely fast, it shouldn't even be a question now.

kerginaldo17 unregistered

Super slow motion is good at first, but boring after a week at the most.

ibend

Posts: 6747; Member since: Sep 30, 2014

it may not be useful for everyday usage.. but it's still great feature to play with :D

marorun

Posts: 5029; Member since: Mar 30, 2015

Depend on your needs. If you dont need it then yess i guess.

mr.reckless562

Posts: 162; Member since: Dec 22, 2016

response to #14 - i need to take super slo-mo of my gf bouncing her tits!! ....but i wont get this phone 4 that. id just use a video editing program after shooting @ 60fps. Usually easier than timing a shot in the real world since the moments in the real world are too random to time.

Lyngdoh

Posts: 319; Member since: Sep 06, 2012

It will be a great feature even for future. To finally capture that bloody UFO!

mr.reckless562

Posts: 162; Member since: Dec 22, 2016

they are using that phone to capture slo-mo of us probably lol

TechGirl90 unregistered

Very Decent Images! :)

kent-gaga

Posts: 609; Member since: Apr 10, 2012

Thank God the photos are a lot less smudgy and over processed But still, the quality gap between the iPhones/Galaxies and the Xperiasis still really really big

marorun

Posts: 5029; Member since: Mar 30, 2015

Its a preproduction demo unit Kent. Also you got to understand thats xperia phone camera are amazing its the software thats crap. i used Camera FV-5 on my sony Z1 and its took better picture than anything out on the market at the time.

miketer

Posts: 460; Member since: Apr 02, 2015

It'll be available from May 7th. I truly look forward for a full fledged review to make a decision.

Khyron

Posts: 388; Member since: Sep 28, 2015

INNOVATION AT ITS BEST SONY good job! but is so disgusting in every article see IPhonearena praising Iphone nor IPhone this iPhone that Iphone iphonearena sucks!!!

mr.reckless562

Posts: 162; Member since: Dec 22, 2016

exactly! sony Always has TRUE innovation. walkman n playstation are my faves. i even bought a MiniDisc player lol. i was tired of scratching my cds, n they held alot of mp3s

remixfa

Posts: 14605; Member since: Dec 19, 2008

i find the lack of detail on the red straps disturbing.

josephnero

Posts: 771; Member since: Nov 16, 2011

this beast will be mine soon

Dallaslegend81

Posts: 11; Member since: Mar 03, 2017

Out of the phones annoyed so far, this one has my attention the most right now. 4k screen, slow motion camera, nice build, great processor. The only thing that kind of kills it for me is tht huge bezels but it's not a total gamekiller. If Samsung doesn't bring their A game with s8. I'll be picking this bad boy up

mimicryXD

Posts: 161; Member since: Apr 03, 2015

totally agree. its not gamechanger if u have dual front facing stereo speakers with very good quality and it gives more than bottom or rear speaker

arming

Posts: 65; Member since: Jul 23, 2016

no matter what function sony put in their ugly phone i am not interested . seems like sony dont even have design team . how couldn't they quit making ugliest phone yet is beyond my understanding .

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