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pixel_binning [2021/02/03 11:50] – Add glossary photosite link Audionut | pixel_binning [2021/02/03 12:07] – minor editing Audionut |
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What happens is that every single Bayer [[/glossary/#photosite]] processed by the camera might be obtained by averaging data from a few photosites (smallest units of the imaging sensor). This averaging process happens in the analog domain. When pixel binning is used, the image received/processed by the camera software is already pixel-binned (the image sensor is not read out at its full resolution). | **This is a more detailed description of [[/glossary/#Pixel Binning]], including specific examples from Canon cameras.** |
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| When the cameras software does not process every single [[/glossary/#photosite]], what happens is that every single Bayer photosite processed by the camera might be obtained by averaging data from a few photosites (smallest units of the imaging sensor). This averaging process happens in the analog domain. When pixel binning is used, the image received/processed by the camera software is already pixel-binned (the image sensor is not read out at its full resolution). |
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Advantages: | Advantages: |
* available binning factors are [[/glossary/#hardwired]]. | * available binning factors are [[/glossary/#hardwired]]. |
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Most Canon cameras use [[/glossary/#Line Skipping]] (a variation of pixel binning, which only combines the photosites from one single line, and discards the data from the other lines in a 3x3 or 5x3 block, see below). It's easier to implement in hardware, but the main disadvantage of line skipping is poor performance with high-frequency details (severe aliasing/moire issues). | Most Canon cameras use [[/glossary/#Line Skipping]] (a variation of pixel binning, which only combines the photosites from one single line, and discards the data from the other lines in a 3x3 or 5x3 block, see below). It's easier to implement in hardware, but the main disadvantage of line skipping is poor performance with high-frequency details (severe [[/glossary/#aliasing]]/moire issues). |
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Canon cameras generally use the following pixel binning modes: | **Canon cameras generally use the following pixel binning modes:** |
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Pure pixel binning modes (without line skipping) - 5D Mark III: | Pure pixel binning modes (without line skipping) - 5D Mark III: |
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Custom binning modes enabled by Magic Lantern (currently available in some experimental versions of the [[/glossary/#crop_rec]] module): | Custom binning modes enabled by Magic Lantern (currently available in some experimental versions of the [[/glossary/#crop_rec]] module): |
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* 1x3 binning: a custom binning technique which operates on blocks of 1 line and 3 columns. It acts as a middle ground between 3x3 (1080p) and 1:1 (full resolution). This mode uses all photosites from the image sensor, by reading every single line, and does not have any noticeable aliasing/moire issues. Also known as [[/glossary/#Anamorphic]]. | * 1x3 binning: a custom binning technique which operates on blocks of 1 line and 3 columns. It acts as a middle ground between 3x3 (1080p) and 1:1 (full resolution). This mode uses all photosites from the image sensor, by reading every single line, and does not have any noticeable aliasing/moire issues. Also known as [[/glossary/#Anamorphic]]. |
* 3x1 binning / line skipping: another custom binning technique, using blocks of 3 lines and 1 column, requiring the same data rate as with 1x3 binning. Not very useful in practice, because of the aliasing/moire issues. | * 3x1 binning / line skipping: another custom binning technique, using blocks of 3 lines and 1 column, requiring the same data rate as with 1x3 binning. Not very useful in practice, because of the aliasing/moire issues. |
{{ https://a1ex.magiclantern.fm/bleeding-edge/lv-binning/binmode-3x3-rcskip-extrememoire.png?100|}} | * 3x3 line/column skipping: from each 3x3 group of photosites, only one photosite is read out; all others are discarded. The layout is a little unusual. [[https://a1ex.magiclantern.fm/bleeding-edge/lv-binning/extreme-moire.html|Extreme aliasing/moiré issues]]. See figure > {{ https://a1ex.magiclantern.fm/bleeding-edge/lv-binning/binmode-3x3-rcskip-extrememoire.png?100|}} |
* 3x3 line/column skipping: from each 3x3 group of photosites, only one photosite is read out; all others are discarded. See figure - the layout is a little unusual. [[https://a1ex.magiclantern.fm/bleeding-edge/lv-binning/extreme-moire.html|Extreme aliasing/moiré issues]]. | |
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FIXME: way too long (move to new page?) (agreed)\\ | FIXME: way too long (move to new page?) (agreed)\\ |