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Thread: Deep Trench Isolation and Cross Talk

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    Deep Trench Isolation and Cross Talk

    It was interesting, at least to me, that Apple just introduced what they call deep trench isolation to reduce cross talk on an iPhone. As I understand it, which may not be well, this is precisely the technology technical camera users want for a Medium Format back to enable and enhance movements. (I don't know personally, still shooting 4x5 film.) If I'm right, I wonder how long for the technology to flow up from the $600 chip to the $60,000 chip.

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    Re: Deep Trench Isolation and Cross Talk

    CMOSIS also has added some technology to help prevent this also, and I believe the Lecia S2 007 has this in it's chip.

    I have not seen any major shifting test of the A7rII to see how it behaves. Hopefully Phase is working on something.

    Paul

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    Re: Deep Trench Isolation and Cross Talk

    I believe the tech announced by apple has more to do with lowering noise. I’m not sure how it would apply to lens cast and improving movements, but seems that doesn’t change the physics of the extreme angles.

    Personally I’ve wondered if the back illuminated sensor design of the a7rII might help with lens cast however.
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    Re: Deep Trench Isolation and Cross Talk

    Quote Originally Posted by Paul2660 View Post
    CMOSIS also has added some technology to help prevent this also, and I believe the Lecia S2 007 has this in it's chip.

    I have not seen any major shifting test of the A7rII to see how it behaves. Hopefully Phase is working on something.

    Paul
    Interesting that Leica would adopt it first for MF Digital in that their backs can't be removed to be put on a technical camera. Odd.

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    Quote Originally Posted by Wayne Fox View Post
    I believe the tech announced by apple has more to do with lowering noise.
    Maybe but the Apple ads specifically mention cross talk and color, not noise.

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    Re: Deep Trench Isolation and Cross Talk

    Quote Originally Posted by Lobalobo View Post
    Maybe but the Apple ads specifically mention cross talk and color, not noise.
    I interpreted their statement to be PR speak for color noise. I'm not sure what they announced is anything that amazing except maybe new to cellphone sensors

    And I still can't see a way that would help with the causes of lens cast.
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    Re: Deep Trench Isolation and Cross Talk

    Quote Originally Posted by Wayne Fox View Post
    I interpreted their statement to be PR speak for color noise. I'm not sure what they announced is anything that amazing except maybe new to cellphone sensors

    And I still can't see a way that would help with the causes of lens cast.
    Well, I don't know. But my understanding is that color cast is caused, at least in part, by signal for one pixel bleeding over to a neighboring pixel, a result of the severe angle. Walls would, it seem combat this. But I may just understand this incorrectly.

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    Re: Deep Trench Isolation and Cross Talk

    Quote Originally Posted by Lobalobo View Post
    Well, I don't know. But my understanding is that color cast is caused, at least in part, by signal for one pixel bleeding over to a neighboring pixel, a result of the severe angle. Walls would, it seem combat this. But I may just understand this incorrectly.
    I'll admit I'm not an engineer, but I believe lens cast is caused because of the difference in wave lengths of light hitting the sensels at extreme angles which are not smooth, but more like little pits. The design of the sensor (such as well designed micro lenses which Sony claimed they used in the a7r sensor) are factors in how severe the lens cast is. But the lens cast itself is more about the characteristics of the surface of the sensor. (that's why the idea of a back illuminated sensor seems to offer promise to reduce lens cast since in theory it could be almost perfectly smooth like a piece of film).

    Apples statement that they are trying to prevent "signal" from affecting adjacent sensels (meaning data from one color of sensel cross talking into another color in the bayer sensor pattern) seems to imply electrons within the sensor leaking. Crosstalk has been an issue in sensor design for a long time.
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    Re: Deep Trench Isolation and Cross Talk

    This seems like something that's of more use on tiny sensors, rather than big ones. Not that having fancy tech is a bad thing, just that at 5-6 microns, pixel wells should already be isolated well enough from each other compared to sensors where the pixels are crammed together 10x as densely.

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