Patent: Quad pixel AF sensor

Canon Rumors Guy

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Canon News has uncovered another Quad Pixel Autofocus (QPAF) sensor patent.
Canon News breaks down why QPAF should be coming in the future.
Right now with dual pixel AF (DPAF) sensors, you can focus reliably while the camera is in the horizontal position and your edge of contrast that you are locking on are vertical.  If the edge is horizontal (or parallel to the camera orientation) then it has extreme difficulty in locking on.  This is because all the pixels are arranged in one direction for dual pixel AF.  What Canon needs is a quad pixel, where the pixel is split up, not once but twice, allowing for different phase different arrangements.
This patent application specifically deals with suppressing the deterioration that may happen with...
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usern4cr

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If this is implemented in the R1, then it would help to define the "groundbreaking" new AF system, as Maximilian mentioned. Since each "quad pixel" would have to cover more area than a "dual pixel" for all the circuitry then I could see the R1 coming in at the 20+MQP (where a pixel is a quad pixel) which is ideal for 4K video as well as plenty for professional stills use. It wouldn't surprise me if the marketing department then decides to call this a "80MQP" sensor and asks the programmers to come up with a new Bayer decoding (up-res'ing) to get 80MP to display & advertise.

Just keep in mind that the IQ and dynamic range will be affected by the increased circuitry on the sensor if that circuitry blocks more of the total light sensed by the sensor. And more false artifacts will occur if the Bayer decoding shifts from 4 cells (RGBG) to 16 cells(RRRRGGGGBBBBGGGG) - but I don't think the marketing department will mention that! ;)

You know, at some point there's going to be so much circuitry and high resolution that I can see Canon finally coming out with a BSI (back-side illuminated) version of their sensors. That's really the only way to keep getting more complexity and resolution and image quality in a FF sensor as you approach the limits of what a non-BSI sensor can do. We may be seeing Canon's first BSI introduction, which would be quite an announcement in itself! Do I think this will happen in the R1? - No, but it sure wouldn't surprise me. And if they want to get a 45M QP sensor and beyond then I think they may be forced to use BSI in the future.
 
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Josh Leavitt

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It would be interesting to see if a quad-pixel AF array is actually going to be four true pixels with independent circuitry for each. It might open up some possibilities for enhancing DR by altering exposure time or signal amplification between each pixel row prior to being merged into a single pixel. Sony's quad Bayer arrays have that functionality and it seems to work pretty well. But yeah, this is probably going to debut on the R1.
 
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Codebunny

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This makes sense where a lot of mirrorless systems struggle a wee bit If lines are going in a particular direction. Somewhat how we needed cross type points. On sensor AF has a lot of innovation waiting to be untapped and it is an exciting time for photographers.
 

H. Jones

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You know, at some point there's going to be so much circuitry and high resolution that I can see Canon finally coming out with a BSI (back-side illuminated) version of their sensors. That's really the only way to keep getting more complexity and resolution and image quality in a FF sensor as you approach the limits of what a non-BSI sensor can do. We may be seeing Canon's first BSI introduction, which would be quite an announcement in itself! Do I think this will happen in the R1? - No, but it sure wouldn't surprise me. And if they want to get a 45M QP sensor and beyond then I think they may be forced to use BSI in the future.
Well, when Canon announces the new R1 sensor as a 21 megapixel quad-pixel back-side illuminated global shutter full-frame CMOS sensor...

We'll have *all* the sensor adjectives. All of them.
 

canonnews

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We have seen Quad-Pixel AF patents since at least 2017, and whether this has anything to do with the rumored R1 is anyone's guess.

From CanonNews ( Japan Patent Application 2017-228829):
I know. but like i said. I think it's more likely we'd see something of the sort to address vertical and horizontal shooting and the AF's ability to lock on more on the R1 versus a global shutter.

I think there's even a GREATER chance we'll just see the 20MP 1DX Mark III sensor again.
 

Mr Majestyk

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Given they discussed QPAF in the orginal DPAF patent way back in arund 2012 it's a long time coming. They also discussed asymmetric DPAF and suing it for HDR. One does not really need QPAF for x-type, they could easily make groups of pixels with DPAF in the perpendicular direction so AF points could consist of just two orientations of DPAF. Would be easier to implement and have greater sensitivity than QPAF.
 

mclaren777

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This seems dumb.

Keep DPAF, but make the microlenses so they split each pixel at a 45º angle.

Problem solved.
 

usern4cr

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This seems dumb.

Keep DPAF, but make the microlenses so they split each pixel at a 45º angle.

Problem solved.
Interesting idea, but it won't work. Then if you have lines half way between these 2 angles then you can't see any difference at all. So you have all the problem and you've reduced your contrast sensitivity by a good amount (about a 35% reduction, I think), and rotated your "blind angle" by 45 (or whatever) degrees.
 

David - Sydney

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Well, when Canon announces the new R1 sensor as a 21 megapixel quad-pixel back-side illuminated global shutter full-frame CMOS sensor...

We'll have *all* the sensor adjectives. All of them.
Well, that would be a 84mp sensor which is entirely possible. DPRAW files never really took off though. Maybe QPRAW will be different

... do do we start talking about megadots (like for EVFs) now instead of subpixels?
 

EOS 4 Life

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this could potentially used as a quad gain output for more dynamic range Just like how the dual gain output works with the current dual pixel sensor where one side has half the gain. With 4 sub-pixels, you can potentially have 4 different gains that get combined into one pixel with significantly more captured DR.
Quad gain output would not surprise me in the RF mount C700 replacement.
I would not expect it in a flagship hybrid mirrorless but I could see it in a flagship cinema camera.