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raw_based_exposure_feedback [2021/02/04 06:45] – more formatting Audionut | raw_based_exposure_feedback [2021/02/04 08:32] (current) – more formatting Audionut |
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* [[#RAW vs JPG]] | * [[#RAW vs JPG]] |
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{{ https://s1.postimg.cc/32j1k4ilj3/Spot_ETTR.jpg?200}} {{https://s1.postimg.cc/77emw8deq7/Spot_Midtone.jpg?200 }} {{ https://s1.postimg.cc/8l1609lw5r/Spot_Highlight.jpg?200 }} | {{ https://s1.postimg.cc/32j1k4ilj3/Spot_ETTR.jpg?200}} {{https://s1.postimg.cc/77emw8deq7/Spot_Midtone.jpg?200 }} {{ https://s1.postimg.cc/8l1609lw5r/Spot_Highlight.jpg?200 }} |
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==== Histogram ==== | ==== Histogram ==== |
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The colored circles in the histogram, warn of overexposure in the color channel | The colored circles in the histogram, warn of overexposure in the color channel |
((This information is derived from the downsized Live View stream. So the percentages reported, may not be an //extremely// accurate representation of the actual percentage, but provides useful information nonetheless.)). Small circles show a very small amount of exposure, with the circles increasing in size. When at least 1 % of the pixels of a channel are overexposed, the numbers inside these colored circles, describe the percentage of pixels that have been overexposed in that color channel. In the above example. 1% of red pixels have been overexposed, 10% of green pixels and 2% of Blue pixels. | ((This information is derived from the downsized Live View stream. So the percentages reported, may not be an //extremely// accurate representation of the actual percentage, but provides useful information nonetheless.)). Small circles show a very small amount of exposure, with the circles increasing in size. When at least 1 % of the pixels of a channel are overexposed, the numbers inside these colored circles, describe the percentage of pixels that have been overexposed in that color channel. In the above example. 1% of red pixels have been overexposed, 10% of green pixels and 2% of Blue pixels.\\ |
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== Histogram Dynamic Range Feedback == | == Histogram Dynamic Range Feedback == |
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The histogram in ML also contains [url=http://en.wikipedia.org/wiki/Dynamic_range]Dynamic Range[/url] feedback. This describes the ratio between the reported white level, and the [url=http://en.wikipedia.org/wiki/Noise_floor]Noise Floor[/url] of the camera, and is only very accurate when the image contains overexposed pixels. | The histogram in ML also contains [[wp>Dynamic_range|Dynamic Range]] feedback. This describes the ratio between the reported white level, and the [[wp>Noise_floor|Noise Floor]] of the camera, and is only very accurate when the image contains overexposed pixels. |
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[img width=300]https://s1.postimg.cc/5f8wn5utwv/DR_hint.png[/img] | {{ https://s1.postimg.cc/5f8wn5utwv/DR_hint.png?200}} {{https://s1.postimg.cc/67ls4wdd33/Histo_DR.jpg?200 }} |
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[img width=400]https://s1.postimg.cc/67ls4wdd33/Histo_DR.jpg[/img] | Note: The brown area in the rear of the histogram represents this noise floor. |
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Note: The brown area in the histogram represents this noise floor. | |
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[hr] | ==== Simplified Histobar ==== |
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[anchor=Histobar][color=green][u][size=14pt][b]Simplified Histobar[/b][/size][/u][/color][/anchor] | |
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| {{ https://s1.postimg.cc/9gxnfpuab3/Histobar.png?200}} |
For LiveView work, there is also the Simplified Histobar. | For LiveView work, there is also the Simplified Histobar. |
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[img width=300]https://s1.postimg.cc/9gxnfpuab3/Histobar.png[/img] | |
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The Histobar is shown here at the top left of the liveview screen. | The Histobar is shown here at the top left of the liveview screen. |
| {{https://s1.postimg.cc/8s4dvpcbwv/Histobar1.png?200 }} |
[img width=400]https://s1.postimg.cc/8s4dvpcbwv/Histobar1.png[/img] | |
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Red indicates overexposure, blue indicates extreme underexposure, and the yellow bar represents the midpoint. | Red indicates overexposure, blue indicates extreme underexposure, and the yellow bar represents the midpoint. |
The blue bar increases in size with increasing underexposure. So the image above shows a small amount of the scene is extremely underexposed, and a full bar would indicate a large amount of the scene is extremely underexposed. | The blue bar increases in size with increasing underexposure. So the image above shows a small amount of the scene is extremely underexposed, and a full bar would indicate a large amount of the scene is extremely underexposed. |
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The midtone point is the median of the scene. For further information, see [url=http://www.magiclantern.fm/forum/index.php?topic=8539.msg80044#msg80044]this post[/url] by a1ex. | The midtone point is the median of the scene. For further information, see [[ml>forum/index.php?topic=8539.msg80044#msg80044|this post]] by a1ex. |
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[hr] | |
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[anchor=Zebras][color=green][u][size=14pt][b]Zebras[/b][/size][/u][/color][/anchor] | |
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[img width=300]https://s1.postimg.cc/6ggsz6eh5r/Zebras.png[/img] | ==== Zebras ==== |
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| {{ https://s1.postimg.cc/6ggsz6eh5r/Zebras.png?200}} |
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Zebras provide a graphical overlay of the areas in the scene which are overexposed, and underexposed. | Zebras provide a graphical overlay of the areas in the scene which are overexposed, and underexposed. |
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[img width=360]https://s1.postimg.cc/1htaknr6en/Zebra1.png[/img] [img]https://s1.postimg.cc/2dd0lxt9zz/97pwi.gif[/img] | {{https://s1.postimg.cc/1htaknr6en/Zebra1.png?200 }} {{https://s1.postimg.cc/2dd0lxt9zz/97pwi.gif?200 }} |
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And a scene showing zebras/histogram, with overexposure, and underexposure. | {{ https://s1.postimg.cc/96atmkc24v/Histo_Zebras.jpg?200}} |
| And a scene showing zebras/histogram, with overexposure, and underexposure. -> See image |
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[img width=400]https://s1.postimg.cc/96atmkc24v/Histo_Zebras.jpg[/img] | |
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As with the histogram, the color displayed by the zebras, represent the color channel in the camera that is overexposed. Again, a Cyan reading is describing overexposure in both the Green, and the Blue channels, Yellow describing both Green and Red channels, and Magenta describing both Red and Blue channels. | As with the histogram, the color displayed by the zebras, represent the color channel in the camera that is overexposed. Again, a Cyan reading is describing overexposure in both the Green, and the Blue channels, Yellow describing both Green and Red channels, and Magenta describing both Red and Blue channels. |
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Unlike the histogram, black describes overexposure in all color channels, and white describes underexposure. [s]This underexposure point describes any data that is within 1 EV of the camera noise floor[/s]. | {{ https://s1.postimg.cc/9b9h4ytg7j/Zebra_under.png?200}} |
| == Raw Zebra Underexposure== |
| This allows you to choose at what exposure the [[/glossary/#underexposure]] zebras will be displayed. 0 EV means that the zebras will be displayed where the amount of [[/glossary/#noise]] in the image, is equal to the amount of signal in the image (the [[/glossary/#SNR|noise floor]]). |
Update: dmilligan added some underexposure adjustment to the zebras. | |
[img width=400]https://s1.postimg.cc/9b9h4ytg7j/Zebra_under.png[/img] | |
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This allows you to choose at what exposure the underexposure zebras will be displayed. 0 EV means that the zebras will be displayed where the amount of noise in the image, is equal to the amount of signal in the image (the noise floor). | |
A general consensus amongst photographers, is that the limit for acceptable amount of noise in images, is 2 EV above this noise floor. | A general consensus amongst photographers, is that the limit for acceptable amount of noise in images, is 2 EV above this noise floor. |
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