Sony debuts 21MP stacked CMOS sensor for smartphones: Digital Photography Review

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Sony has unveiled a new stacked CMOS image sensor for use in smartphones. Called the IMX230, it features 21 effective megapixels, on-chip phase detection AF and 4K video recording. The chip is a 1/2.4-inch type with square pixels measuring 1.12um x 1.12um each. Video of up to 4K (4096 x 2160) resolution is available with HDR function (also available in stills mode).

The sensor uses a backside-illuminated configuration previously introduced by Sony called Exmor RS, with a layer of signal processing circuits below a layer of backside-illuminated pixels. It boasts a total of 192 AF points, with signal processing incorporated into the image sensor itself. On-sensor phase detect autofocus and processing should ultimately result in faster and more accurate autofocus with improved subject tracking.

Sony's previously-introduced HDR Movie feature makes its way to this chip, this time offered with 4K recording, and can be used in stills shooting for the first time as well.

Tucked into the press release is a mention of another upcoming sensor, a 16MP stacked sensor with phase-detection AF by the end of the next fiscal year. The IMX230 unit will begin shipping in April 2015.

Press release:

Sony Announces the Exmor RS™, the Industry's First*1 Stacked CMOS Image Sensor with an Image Plane Phase Detection Signal Processing Function for High-Speed AF

*1: As of November 17, 2014

Tokyo, Japan - November 17, 2014 - Sony Corporation (hereafter "Sony") today announces the commercialization of the Exmor RS™ IMX230 for smartphone cameras and other devices requiring increasingly sophisticated image-capture functionality. With 21 effective megapixels, this stacked CMOS imaging sensor features compact size, higher image quality, and improved functionality. This is the industry's first CMOS image sensor for smartphones to be equipped with an onboard image plane phase detection AF signal processing function to achieve excellent focus tracking of fast-moving subjects. The High Dynamic Range (HDR) function, which captures both backgrounds and subjects clearly and vividly even in high-contrast scenes such as backlit locations, now supports high-resolution still images and 4K video recording. This new CMOS image sensor will ship in April 2015.

Model name	Shipment date (planned)	Sample price
Type 1/2.4 21 effective megapixels*2 stacked CMOS image sensor IMX230	April, 2015	2,100 yen

Rather than the traditional back-illuminated CMOS image sensor's support substrate, the Exmor RS™ uses a chip consisting of signal processing circuits, on top of which is stacked a pixel section consisting of back-illuminated pixels for an original stacked construction. This kind of stacked CMOS imaging sensor, which delivers superior image quality and high functionality in a compact size, was first commercialized by Sony in 2012.

The new IMX230 is a type 1/2.4 stacked CMOS image sensor with a significantly improved 21 effective megapixels, and it is also equipped with a newly developed signal processing function. These features fulfill the growing needs in smartphone photography for high-speed autofocus (image plane phase detection AF) and clear, high-quality capture of bright and dark areas even in backlit scenes (HDR imaging). Image plane phase detection AF is a technology used in mirrorless interchangeable-lens cameras, and HDR imaging now supports not only 4K (4096 x 2160) high-resolution videos but also still images. Sony also plans to extend the lineup by adding a 16 effective megapixels stacked CMOS image sensor equipped with image plane phase detection AF and HDR imaging functions by the end of the next fiscal year.

IMX230 Main Features

Image plane phase detection AF

This function enables the camera to capture quick-moving subjects and makes accurate, high-speed autofocus tracking possible when shooting still images and videos, such as kids and animals constantly on the move and other fast subjects including athletes at sporting events. Dedicated image plane phase detection AF pixels are discretely incorporated into the screen of the image sensor, and the distance to the subject (range) and lens position for focusing are calculated based on the information obtained from these dedicated pixels. Up to 192 AF points can be used. All of this is instantaneously carried out by the stacked CMOS image sensor's internal image processing circuits, making it easy to enjoy shooting photos and videos of fast-moving subjects on a smartphone or other device.

Image plane phase detection AF function using 192 AF points

High Dynamic Range (HDR) imaging

This function enables the camera to record still images and videos that reproduce details and rich gradations in the highlights and shadows of high-contrast scenes, such as those found in backlit environments. This is made possible by setting two different exposure conditions and applying the appropriate signal processing to the image information obtained from each condition. Through improved pixel placement and signal processing, this new HDR imaging function is now compatible with both video recording and, by popular demand, still image capture, the latter a feature that was not available previously*3. The enhanced resolution and generation of images with a wide dynamic range enable a high level of visibility and the production of images with vivid backgrounds and subjects, even in backlit conditions. This function is also compatible with 4K (4096 x 2160) high-resolution video recording.

*3 The HDR movie function announced on January 23, 2012 supported video recording only.

HDR imaging sample (right) with the IMX230 type 1/2.4 21 effective megapixels*2 stacked CMOS image sensor

Traditional HDR movie (left) using IMX135 3.2 effective megapixels*4, and sample using the IMX230 21 effective megapixels with new HDR imaging (right).

*4 When using the HDR movie function, the effective pixel count is reduced to 1/4 of its original number.

Model name	IMX230
Number of effective pixels	5344 (H) x 4016 (V) 21 megapixels
Image size	Diagonal 7.487mm (Type: 1/2.4)
Unit cell size	1.12um (H) x 1.12um (V)
Frame rate	Full: 24fps Movie: 4K (4096 x 2160) 30fps, 1080p 60fps, 720p 120fps
Sensitivity (standard value: F5.6)	78mV
Sensor saturation signal (minimum value)	330mV
Power supply	Analog: 2.5V Digital: 1.1V Interface: 1.8V
Key features	Image plane phase detection AF, HDR imaging, white spot correction, NR
Output	MIPI (4 lane)
Image format	Bayer RAW

Comments

Total comments: 95

You can't bend the laws of physics. Sensors can be made any which way, but the small ones will never, ever match the larger ones. Back illuminated, electron-multiplying, it doesn't matter. They are modest enhancements that produce a slightly better product, but a 1/2.3" sensor will never be a m4/3, APS, etc.

0 upvotes

Never?
Thats arrogance, our "truth" is just a particle of what the truth really is, open your mind.

Comment edited 22 seconds after posting

1 upvote

Yes, of the same generation. The sensor in the G7X is as good as the first 5D in terms of noise and DR....yetthe larger format can produce sharper results.

0 upvotes

Most people just want good enough. Does it matter if it isn't the best?

1 upvote

@Marc, @Rich is right you know. Maybe you think reality is difficult. But, reality is what you need to consider when making real things. Dreaming, everything is possible. Dreaming is not "opening your mind", rather closing.

0 upvotes

Many in the past said we would never fly, and here it is... closing or opening depends on your point of view.

1 upvote

Accepting everything is closing the possibility to knowledge.

Saying that we can never fly is lack of imagination though. I would never ever have accepted such nonsense in the day before aeroplanes.

Saying that smaller sensor can have better noise behaviour than larger is just plain strange. Its like saying one kilo weights less than one gram. Accepting such truths may be funny and creative in some contexts, mainly fiction, but it seldom is of any use if you shall build an artefact of technology.

Comment edited 3 minutes after posting

0 upvotes

smaller sensor are actually significantly better per area than large sensors. The difference of course is that images from small sensors is enlarged so much more at any given output size that their flaws are also magnified. A small sensor would have to be several times better than a large sensor for this to be made irrelevant. And it is unlikely that large sensor tech will stagnate at such a level compared to small sensor tech.

There is also the issue of DOF control, which perhaps can be overcome through software and processing with unique solutions such as lytro, but those come at the cost of complexity and usability.

0 upvotes

Yes, smaller sensors just have to be better per area in order to be able to compete at all.

0 upvotes

But that's the point of this advance…by putting circuitry behind the sensor, rather than taking up area that should be capturing photons, you get an all-else-equal bigger sensor.

Then, there's the constant improvement in the physics of converting photons that impinge on a chip, into electrons. And optical improvements that get more photons onto the chip.

Lots of improvements here, and ahead. Hardware. Haven't even touched smart software.

1 upvote

Interested in small sensor tech or not, every photog should be grateful to the smartphone industries. Compared to photography alone smartphones is a BIG revenue business - and lots of $$ are spent in making these little cams better. Bigger sensors will benefit from this development, too - and get cheaper as well as the development costs will be returned mostly by smartphone buyers (uhh, us again?). :)

Comment edited 30 seconds after posting

6 upvotes

Well... while I do not mean to argue with what you said, I think most "developments" come first to the big sensors.
Also the "incredible small pixels" are not to come too soon to the bigger sensors, because it's simple pointless.

But imagine how many pixels a 24x36 mm sensor will have if it will use this tech :))

1 upvote

What developments came first to large sensor?

Large sensors were mostly CCD, small sensors CMOS. CMOS trickled up to large sensors, just now hitting medium format.

The larger you go, the fewer users of your sensor, the slower it will change to market. The 5D has about a 5 or 6 year product cycle, a cell phone 1 or 2.

11 upvotes

I don't think there are any BSI m43, APS, or FX sensors, either.

0 upvotes

What developments came first to large sensor? How about layered sensor technology, such as that in the Sigma cameras? How about on-chip phase detection AF?

Yes, the BSI configuration came to the small sensors first. In fact, it is exclusively in the realm of the small sensors. Maybe it will come to the large sensors one day, but it hasn't yet. What other technologies have been put into small sensors that weren't put into large sensors first?

1 upvote

Already stated: CMOS was first used on small sensors. I'm sure there are other examples.

The argument that all sensor developments progress from large to small is clearly false. Reality is far more interesting than that.

0 upvotes

21 mpix for FB and Instagramming???

4 upvotes

Or editing, cropping and/or printing.

0 upvotes

OSPDAF for cellphone sized sensors is a joke: these tiny 192 points are just can't get enough light
This is strictly the place for software predictive autofocusing

1 upvote

I remember people saying that 10 MP was too much on an APS-C sized sensor. Obviously you are mistaken, if they decided to make a sensor with such tiny photo-sites. They're not stupid. One day we might see 100 MP sensors in smartphones.

2 upvotes

@Scottelly
You are not relevant here. At all.

0 upvotes

With each passing year, the comments get worse. Sad.

8 upvotes

Welcome to the internet. Free speech in action.

3 upvotes

Now you can find my photo.

0 upvotes

I feel Sony usually do well whenever they come to any business.
We don't really have any bad experience of their products if we use them properly.In our house most of the appliances and electronic devices are manufactured by Sony.We even had radio made by Sony belonging to 4 decades before still functioning well.Viva Sony.
You see when they came to DSLR how well they could compete with big brands like Canon and Nikon.
Also thanks to dpreview for their endeavor in providing us on time news of manufacturers.

1 upvote

The technology of sensors is amazing.
Sadly the physics of light refraction has not changed.
Small sensor, small lens, big limitations.
However for most users who are happy with a selfie quality image how much do these technological advances really mean?

10 upvotes

Camera snobbery at its finest.

21 upvotes

i stop enjoying photography ever since i do it professionally. then came LX1, the love was rekindled. now that i am getting of age, very grateful for the advancement in phone cameras, which allows me to hv a camera with me whenever i am outdoor.

10 upvotes

iphone takes decent pics. Better than what we thought was "state of the art" less than 10 years ago.

4 upvotes

And the old axiom, "The best camera is the one you have with you...", is as true now as ever - cell phones notwithstanding.

2 upvotes

Sooner or later...

Sony will realize...

Hey! Why not put a cell phone into our high end compact and mirrorless cameras!

"Keep on posing my dear, while I take this call..."

2 upvotes

there is already one..samsung k zoom

3 upvotes

Phase detect AF for phones, hehe, as if phones need to focus at all.

0 upvotes

yes they do, as with a sensor size almost of a compact camera ...

5 upvotes

You've never actually used a panfocal cell phone camera, have you? I have (iPhone 3G). It was not pretty.

4 upvotes

Nothing to rave about, just a normal evolution of the technology.

With integrated signal processing, NR, HDR and nice video capabilities, this is probably gonna be a hit for smartphones.

And once competent phase detection AF becomes standard in smarphones, it better be a standard in mirrorless by that time. I'm looking at you Olympus, the E-M5 successor better have one of those nice AF systems on board.

5 upvotes

I'll say this. Everyone just think about where we were with sensors 5-7 years ago. FF, APS-C, p&s, cell phone, etc. Now look at today. Back then, many would have not thought a 1" sensor could do what it does today. Nor would many have thought of a camera phone being anything that could compete with a "larger" p&s sensor. Yet, here we are.

In 5-7 more years, I'd be willing to bet that high end camera phone sensors will be producing IQ with very good resolution up to ISO 1600 and 3200. We'll see 1" sensors performing at levels of most APS-C (think a6000, XT1) of today and APS-C going beyond what standard FF does today. 4/3 will also progress. FF? Watch out. Look at that Sony A7S. I think ISO 56,000 will be a walk in the park for most.

PDAF and best AF tech today will also look pretty slow as well. It all changes, always does. Sit back and enjoy the ride :-) Of course, I could be completely wrong too LOL!

7 upvotes

"I'll say this"...
Who the hell asked you?

0 upvotes

5-7 years for 1-2 stops improvement? I expect it to happen exactly next year. Sony is about to introduce new sensor tech that makes a much bigger jump forwards.

3 upvotes

Keep it civil. There is nothing wrong with his kwa_photo's comment. No need to respond like you know everything already. I too think the progress has been pretty amazing. I have been doing photography in a serious way since I was 12 years old - 56 years ago and the pace of change in the digital age has been like going to warp speed. Everything is improving by leaps and bounds and the available resources for learning about photography today are equally astounding. Prices have gone through the roof, of course, but I guess people buy these products or the manufacturers would not make them.

30 upvotes

tagomilonga - You are being unkind. Please observe that your kindness or lack of it is reflected in the quality of your life. Politeness is never out of fashion.

0 upvotes

tagomilonga: as this is a public forum and this is the comment section, I would say everyone's comments are welcome.
Who are you to judge?

14 upvotes

The last 5-7 years of camera development have been driven by economics. First truly compact then affordable DSLR generated a lot of money from consumers and enthusiast in that time. That pushed forward 1/2.7" and APSC sensor development and value-add features.
Then the market was saturated. Everyone who wanted a camera had one.
Fortunately two things then happened. People started changing their mobile phones every 2 years. DSLR owners started looking for second cameras and lighter alternatives.
In many ways, this saturated market is driving more innovation - It has to in order to persuade us to buy *another* camera when we probably have a perfectly fit-for-purpose DSLR from 5 years ago.

0 upvotes

I'm actually surprised they haven't made an MoS2 (molybdenite) sensor for smartphones yet. THAT would be a step forward, and whoever is the first sensor manufacturer to start producing them will gain a huge amount of market share.

http://www.sciencedaily.com/releases/2013/06/130612133101.htm

0 upvotes

Doesn't the iPhone 6 camera sensor offer the same: on-sensor PD AF & one-shot HDR?

4 upvotes

Since Sony builds the camera for the 6, I doubt it is the same (maybe iphone 7)

0 upvotes

I didn't say the sensors were the same, I merely said that the iPhone 6 sensor offers the same headline features (on-sensor PD AF & one-shot HDR) as this sensor (obviously with a different resolution).

0 upvotes

No, it's a "regular" BSI (Exmor R) sensor in the iPhone and not a stacked (Exmor RS) sensor as seen here. With much lower resolution for stills, no 4K mode, slower read out and no on chip HDR processing (rather trough the phone software after 2 quick exposures instead).

Comment edited 5 minutes after posting

3 upvotes

I was just pointing out that headline feature of this sensor is on-sensor PD AF. Which was also the headline feature of the iPhone 6 camera. And this is only the second time that this feature has been implemented on a phone camera sensor. Why is that not worth mentioning?

0 upvotes

The headline literally says:
"the Industry's First*1 Stacked CMOS Image Sensor with an Image Plane Phase Detection Signal Processing Function for High-Speed AF"

Notice the word "stacked". Key difference.
And it's not the second implementation. The first practical implementation on a phone camera was on the Galaxy S5, using a Samsung isocell BSI sensor with PDAF. After that came the Note 4 and iPhone 6(plus) using 2 different Sony BSI sensors with on sensor PDAF. This is the first time it's combined with the technology that followed up on the BSI designs back in 2012: stacked (BSI) CMOS sensors. Once implemented, that would make it the third time we see PDAF on a smartphone.

Comment edited 4 times, last edit 4 minutes after posting

6 upvotes

When I read stacked and on-sensor PD AF, I only care about PD AF because stacked like BSI isn't tied to any clear sensor performance improvement. Thus, for the actual user of a camera what matters is PD AF and the rest is effectively technical implementation details.

And I stand corrected on the iPhone 6 being first. But why doesn't the article (the part written by DPreview) refer to these two smartphone families (Galaxy and iPhone) as already having PD AF?

0 upvotes

"because stacked like BSI isn't tied to any clear sensor performance improvement"

In principle it does, see Ziptronix technology used by Sony though a license agreement, which allows for electrical connections with the bond without the need for TSV's, thus higher efficiencies (less wasted light gathering space) with higher pixel densities. Ceteris paribus (including total pixel count per given area) of course.

I agree that it would have been nice to mention current PDAF implementations in smartphones.

Comment edited 5 times, last edit 7 minutes after posting

0 upvotes

The isight camera on iPhone 6 is indeed exmor RS. According to chipworks

0 upvotes

Well, given that the iPhone 6 has been on the market, how long now? and Sony are making this announcement now, let me guess...... they're not the same?

0 upvotes

I never said they were the same, just that they use the same technology (PD AF, one-shot HDR).

0 upvotes

Thicker slab smart phones are going to be the in fashion...

1 upvote

Cant wait till they scale this up to 1-inch type. Imagine an RX10 with 24-200/f2.8 for Panasonic FZ1000 (24-400) with PDAF. Goodbye m43.

7 upvotes

Why would that affect MFT ? Panasonic's first generation DFD already proved to be as good or better than current OSPDAF, and it's likely to only get better. Plus, MFT might very well get these sensors from Sony, would you then say goodbye RX10?

3 upvotes

Seriously Jogger? So, larger sensors are no improvement, and we'll also see the death of APS-C and FF?

6 upvotes

Large sensors would improve too. But for those the m43 provides good enough IQ for smaller sizes, this would catch them sooner than APC or FF.
For those who are buying cameras for size issues this would make more sense. Not all APC and FF buyers are after size, they are, many times, towards DOF

0 upvotes

Pentax 645 days are numbered obviously. ;-)

22 upvotes

Unless they add a keypad, annoying ringtone and make the Pentax vibrate.

24 upvotes

Damn, just dropped a wedge on a 645Z

0 upvotes

I worship everything Sony and loath EVERYTHING else! Or wait. I meant Canon! Or. Just a minute......

6 upvotes

Not interesting - no on-sensor "see impossible" function.

Comment edited 28 seconds after posting

2 upvotes

This is just silly. The details will be smeared. Any 8 megapixel DSLR from ten years ago will out resolve this crappy sensor. Adding more megapixels is just a bad idea. But sure, people will still buy it and think it is the best thing since sliced bread.

4 upvotes

are you sure? even if you normalize down to the kind of resolution smartphone shooters actually use (say 2-4MP)?

8 upvotes

@Simon

1, What's the point in first slicing the image to 21 MPix, if you subsequently *have to* downsample to obtain decent imagery ?

2, Sure, 8 MPix Dslr will in general provide far superior results. Only in special cases (very good light, highly contrasty details), 21 Mpix on 1/2.4 would actually deliver the promised resolution.

2 upvotes

This is how I view the 1" sensors as well. I do have a Sony RX10 (20mp). I treat it like it's a 14-16mp sensor for normal use and down-sample it from the 20mp. The resolution is still pretty competitive but it really does seem to improve the overall IQ IMO. It prints to 13x19" (largest I've tried so far with it) very well.

If I'm at ISO 1600-4000, I treat it like a 10mp camera and down-sample to that and the noise is well "controlled" if you get my drift. Mind that I do not usually "crop to zoom" like some people do, I try and get everything right in camera first.

Following this logic, I see Simon's point. If you are staring at 20+ MP you can do this. However, if you are starting at 8-12mp, I really don't want to down-sample to 4-6mp.

I have an iPhone 5s. I don't down-sample at all. I take it for what it is. A camera on a phone that does a great job at low ISO's. That's it.

1 upvote

@sebiruns. Are you making calls on your DSLR?

0 upvotes

I tend to agree, any DSLR from the past 10 years will beat any smartphone. However, I don't typically keep my DSLR in my pocket and carry it literally everywhere I go. So the comparison means about as much as saying a banana tastes better than a phone.

4 upvotes

I just question why there is a megapixel race in the smartphone world while in professional photography (see Nikon D4s, Canon 1D C or Sony A7s) less megapixels is the trend to optimize speed and lowlight performance. We had megapixel races in the compact camera market and it ended because results did not improve. In video cameras there is also the trend to use sensors with less megapixels. So why is it a good idea to keep pumping up this spec on the smallest of all sensors? Hits me as a stupid idea.
@kwa photo: I also use a RX100. It delivers good results, but we don't know if they could be better with a different sensor design. It is certainly better to have a 1inch sensor with 20mp than to have a smaller sensor with the same amount of pixels. Why the focus on lowlight performance. The smartphone is the camera we take everywhere. So it should try to be versatile and not just good in perfectly lit conditions.

0 upvotes

sebiruns you got it all wrong.

" Any 8 megapixel DSLR from ten years ago will out resolve this crappy sensor.

It should have read:

"I would prefer any 8 mp DSLR from ten years ago to this sensor."

How do you know it is crappy? Have you seen the photos?

0 upvotes

Agreed. That was too harsh. It is still a smartphone sensor, though. So greatness cannot be expected.

0 upvotes

4 years ago this chip was unimaginable. Now that it is here Canon is still where they were 4 years ago talking about the “Impossible”.

29 upvotes

You sound like someone who has Sony shrine at home. A missionary for corporate entity. Rather wierd :-)

6 upvotes

You sound like some delusional fan who's believing his own psycho-babble. Put the shoe on the other foot & take a long look in the mirror kid ;-)

1 upvote

Right, because four years ago Canon hadn't come up with on-chip PDAF, *before* Sony. Quit the wanky fanboyism and just enjoy the fact that these companies are improving all the time.

1 upvote

And the worst part is that 4 years from now, they will still be 4 years ago.

3 upvotes

I can’t think of two fundamentally different devices than a phone and a camera. Yet we still find a way to make them one and the same.

4 upvotes

The ultimate goal should be for Sony to make a phone that is so good, they can't sell any cameras.

5 upvotes

Confucius say, phones are just cameras that send electrical pictures of your words.

2 upvotes

Do you lament that phones have calculators and web browsers, too? I mean a phone is not a calculator and yet you can perform calculations on a phone. That's totally messed up. And we also know that phones are not computers, and yet I can surf the internet and send email with mine! And if I wanted to music on the go, I would have bought an ipod! Thanks for cluttering up my phone with this terrible itunes and pandora!

1 upvote

I can't think of two fundamentally SIMILAR devises than a phone camera, and a stand alone camera.
Basically they are one and the same as far as photography goes.

0 upvotes

Canon still thinks they can do better.

8 upvotes

Hey Canon. “Imagine” This!

16 upvotes

"Hey Sony. We see impossible"

2 upvotes

Sony - "Imagine Profits"

0 upvotes

SH!T just got REAL!

Comment edited 2 times, last edit 32 seconds after posting

6 upvotes

Next January's introduction of their large-sensor camera line will be VERY interesting. Watch for an RX100 IV with on-sensor PDAF. And say goodbye to Nikon's Series 1. I still don't understand why they didn't introduce a fixed-lens CX sensored compact in 2011 instead of dinking around with an ILC.

13 upvotes

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