June 23, 2014

Sony's New Curved CMOS Sensor Could Mean Better Images & Sharper, Faster Lenses

sony curved cmos sensorDigital imaging sensors are traditionally small, flat devices that convert images, which are focused onto the sensor by a lens of some sort, into an electronic signal that can then be processed in numerous ways. With very few exceptions, every digital sensor in use today is flat. However, in a few year's time, that may not be the case, as Sony's device manager Kazuichiro Itonaga recently showcased two new curved CMOS sensors, one a 43mm full frame sensor and the other a much smaller 11mm 2/3 size sensor. These new sensors are reportedly up to twice as sensitive as traditional CMOS sensors, and they have the potential to make our lensing systems simpler, faster, and sharper.

In order to understand why the development of curved sensors is a significant one, it's important to first understand some of the inherent limitations of flat sensors. First up is the issue of field curvature. In this excellent article from DPReview, Rishi Sanyal breaks down what field curvature is and why lenses need complicated optical corrections in order to combat field curvature when projecting onto a flat surface.

Field curvature results from the fact that the effective focal length light rays experience decreases the more off-axis light rays are from the lens' optical axis (the optical axis is defined by a line running from infinity through the center of the lens). In other words, the more off-axis a light ray is, the further in front of the focal plane (defined by focused on-axis rays) it falls.

field curvature diagram

Enter Sony's new curved sensor. Theoretically, this curved sensor would allow lens manufacturers to create simpler lenses (with fewer elements and larger maximum apertures) that work with field curvature instead of against it, since light hitting the lens from oblique angles wouldn't need to be optically corrected in order to be projected onto a flat imaging plane.

Beyond the possibility of simpler and higher performance lensing systems, curved sensors also have the potential to offer higher performance than their flat counterparts. Apparently, the manufacturing process for these sensors, which is done by a custom machine that bends flat sensors into a convex shape, actually increases the inherent performance capabilities of the sensor.  In this article from IEEE Spectrum, Rachel Courtland describes how curved sensors have the potential to be more efficient.

curvediagramhalfcolumn-1402453918753Photodiodes at the periphery of a sensor array will be bent toward the center, which means light rays will hit them straight on instead of obliquely. What's more, the strain induced on a CMOS sensor by bending it alters the band gap of the silicon devices in the sensor region, lowering the noise created by "dark current" — the current that flows through a pixel even when it is receiving no external light.

According to Sony's engineers, the curved sensor that they debuted last week is 1.4x more sensitive at the center of the sensor and 2x as sensitive at the edges, which means that the low-light potential of these sensors is mind-blowing, especially when paired with any newly designed large aperture optics designed specifically for these curved sensors.

sony curved cmos sensor

Of course, there are some drawbacks to curved sensors as well, chiefly that their only applications -- at least at this point -- are in fixed lens cameras, since the curvature of the sensor has to match the field curvature of the lens projecting onto it. In order for interchangeable lenses to work in an imaging system with a curved sensor, the sensor itself would also have to be easily interchangeable, something which would likely be too time-consuming for most photographers and filmmakers.

In the near future, we're not likely to see curved sensor technology make its way into the filmmaking world, largely because of the issue with interchangeable lenses described above. However, the 43mm full-frame sensor could very well find a home in cameras like Sony's RX1, and maybe even some of Sony's fixed-lens camcorders. The 11mm sensor is more likely than not going to find its way into smartphones and similarly sized imaging devices.

What do you guys think about Sony's new curved sensor? Will this technology have a significant impact in the worlds of photography or filmmaking? Let's hear your thoughts down in the comments!

Link: Sony's Curved Sensors May Allow for Simpler Lenses and Better Images -- DPReview

[via Spectrum & FStoppers]

Your Comment

25 Comments

perfect match for a curved tv (is obviously a joke)

June 23, 2014 at 5:02PM, Edited September 4, 11:56AM

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Daniel

Simple solution - integrate lens and the sensor, switch both at the same time.

June 23, 2014 at 6:19PM, Edited September 4, 11:56AM

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That's a helluva money right there. Well, premium ones already cost a fortune, so not so much then.

July 2, 2014 at 12:34AM, Edited September 4, 11:56AM

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Natt

I proposed this years ago and people laughed at me. WTF.

June 23, 2014 at 6:29PM, Edited September 4, 11:56AM

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Harry Pray IV

to whom?

June 23, 2014 at 9:45PM, Edited September 4, 11:56AM

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bunda

CML and others.

June 24, 2014 at 9:00AM, Edited September 4, 11:56AM

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Harry Pray IV

This is a quote that is attributed to Arthur Schopenhauer that you may relate to.
"Every truth passes through three stages before it is recognised. In the first it is ridiculed, in the second it is opposed, in the third it is regarded as self-evident."

June 27, 2014 at 4:05AM, Edited September 4, 11:56AM

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Francisco Lima

film.

June 23, 2014 at 6:30PM, Edited September 4, 11:56AM

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brawk

Film is curved as it goes around the sprockets. That's why film is so good.

June 23, 2014 at 8:52PM, Edited September 4, 11:56AM

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Ed David

Film is held flat in the gate, so, not curved. At least not during exposure.

June 23, 2014 at 11:31PM, Edited September 4, 11:56AM

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Kurt Fillmore

Right you are. And even if film were curved at the film gate, it would only be curved in one dimension - up/down or left/right along the length of the film, depending on how the film was run through the camera. These new sensors are more cup-shaped, curved in two dimensions - left/right and up/down - to then take up a third dimension - depth.

I wonder - if film were in fact curved at the gate (in one dimension), I wonder if an anamorphic lens could be used to correct for that curvature. Just idle musings.

June 26, 2014 at 11:49AM, Edited September 4, 11:56AM

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Great news for gopro, or bad since Sony offers a competing product.

June 23, 2014 at 9:37PM, Edited September 4, 11:56AM

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david

GoPro has a competitor? LOL.

June 26, 2014 at 5:50AM, Edited September 4, 11:56AM

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Gene

@other Gene: Panasonic has a gopro type device, shoots 30fps at 4k. Lipstick shape, used it last week and amazing results at 4k. Old review:
http://www.4kshooters.net/2014/06/17/pa ... camcorder/

June 26, 2014 at 6:53AM, Edited September 4, 11:56AM

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Gene

Top GoPro model is using Sony sensor anyway so more they sell the more money Sony will make ;)

June 29, 2014 at 12:13PM, Edited September 4, 11:56AM

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Kuk

Nature...
Doing Curved sensors since dinosaur's era! ☺

June 24, 2014 at 12:44AM, Edited September 4, 11:56AM

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Theuer

Good point. haha.

June 14, 2016 at 8:59AM

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Lester Lauritzen
Director, Motion Designer, VFX Artist
26

Fantastic news. At least for the manufacturers, since it will cut off use of all old lenses, and requires a complete new range specifically calculated for that sensor.

June 24, 2014 at 8:23AM, Edited September 4, 11:56AM

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Thyl Engelhardt

Or maybe we'll see a lens accommodating sensor. :) That can bend when needed, to whatever curve needed, and flatten out to work with our old lenses. This would be ideal, probably won't happen.

June 14, 2016 at 9:01AM

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Lester Lauritzen
Director, Motion Designer, VFX Artist
26

Someone should write an article about canon ultra sensitive sensor that they say they were working on back in 2012 i think.. they even showed footage of it pointing at the sky night time and you can see the milky way... i think that sensor is canons only hope to catch up with sony and everyone else before it's too late.

June 25, 2014 at 10:30AM, Edited September 4, 11:56AM

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Why not build a camera with an integral focusing lens system in front of the sensor, but behind the multi-purpose lens mount? The assembly would add depth, but it wouldn't necessarily have to be substantial, depending on the size of the sensor. That would allow more conventional lenses to be used with various crop-factors or overlap. We already deal with similar issues between MFT, APS-C, Full Frame, and the slew of other lens adaptors.

June 26, 2014 at 12:18PM, Edited September 4, 11:56AM

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Scott A. Baker

No need to change sensors for different lenses. What is needed is a new set of lenses all designed to focus on the curved plane of the sensor.
One of the reasons some old film lenses, those with very small rear elements, don't work so well with digital sensors is that the light comes so obliquely to the edge of the sensor that not all of it reaches the bottom of the perpendicular wells. Even greater edge fall-off than there is with the same lens on film.

June 26, 2014 at 3:00PM, Edited September 4, 11:56AM

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Jack

No need for totally new lenses when the older ones can be partially rebuilt without the extra elements used to
work with flat sensors. Any of the companies that rebuild still lens into cinema lens should be able to do that.
If anyone knows a reason why tht can not be done I would be curious to hear it.

June 26, 2014 at 10:55PM, Edited September 4, 11:56AM

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Gary Simmons

Looks like Sony wants to be always in the innovation forefront! In the last twelve months that I have bought and used an a77, (after so much of debate to buy the affordable best), I must have been tempted by a dozen more newly products in that price band, by Sony!
Sony, go ahead and woo new and more customers, but please do something for the old loyals who carried your name on their cameras, in their Flickr sets, straps, bags and sold it to nikanons. Some fw updates to keep us happy and even more loyal.

June 27, 2014 at 2:37PM, Edited September 4, 11:56AM

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Rajaram

Perhaps if the cost of lenses come down due to simpler optics, someone might be able to combine the lens with the sensors for complete compatibility and eliminate the problem of sensor/lens matching.
You might even be able to buy a lens/sensor combo for different applications.

July 1, 2014 at 8:00PM, Edited September 4, 11:56AM

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Wayne