playground:playground
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====== Exposure to the right (ETTR) ====== | ====== Exposure to the right (ETTR) ====== | ||
- | Exposure to the right (ETTR) is a technique of setting the exposure of a scene such that few or no pixels are are over exposed (blown out) thus maximizing the information captured without loosing information to over-exposure. | + | Exposure to the right (ETTR) is a technique of setting the exposure of a scene such that few or no pixels are are over exposed (blown out) thus maximizing the information captured without loosing information to over-exposure. |
- | There are two methods of using ETTR. | + | For more information on ETTR, see these articles on Luminous Landscape: |
+ | * http:// | ||
+ | * http:// | ||
+ | |||
+ | There are two methods | ||
+ | |||
+ | The first method involves taking 2 images. | ||
+ | |||
+ | The second method uses the live view momentarily to run through a series of exposures until the exposure is correct | ||
ETTR sets the shutter speed and ISO. It does not change the aperture setting thus not altering the depth of field of the scene. | ETTR sets the shutter speed and ISO. It does not change the aperture setting thus not altering the depth of field of the scene. | ||
- | In the Expo Tab (Exposure Menu of ML) you will find Auto ETTR. | + | In the Expo Tab (Exposure Menu of ML) you will find Auto ETTR: |
{{: | {{: | ||
- | Pressing the Q button brings you to the settings menu of the ETTR function: | + | Pressing the **Q** button brings you to the settings menu of the ETTR function |
+ | |||
+ | ==== The Settings ==== | ||
{{: | {{: | ||
- | ==== The Settings ==== | + | **Trigger mode**: Always ON, Auto Snap, Press SET, HalfS DblClick. |
- | **Trigger mode**: Always ON Auto Snap, Press SET, HalfS DblClick. | + | |
- | **Slowest shutter**: 1/60 Here you can adjust | + | |
- | **Highlight Ignore**: 0.2% This number tells the system in how many bright (highlight) pixels to ignore when calculating ETTR | + | |
- | **Midtone SNR limit**: 6 Is defined in EV levels in the Midtones | + | |
- | **Shadow SNR limit**: 2 Is defined in EV levels of noise form 1 to 4 EV. The higher the SNR the less noise. | + | For Timelapse set it to **Always on**. |
+ | |||
+ | With **Always on** and **Auto snap**, you should definitely enable Zebras and Histogram to see if the settings it choose are correct. | ||
+ | |||
+ | **Slowest shutter**: 1/60 The slowest shutter that will allow for the current scene. . For a night time lapse set it to 30 seconds. | ||
+ | |||
+ | **Highlight Ignore**: 0.2% Percentage of (highlight) pixels to ignore when calculating ETTR. This is used if you want to allow overexposure in the highlights, for example room lights. | ||
+ | |||
+ | **Midtone SNR limit**: 6 Is defined in EV levels of noise in the Midtones form 1 to 8 EV. The higher the SNR the less noise. | ||
+ | |||
+ | **Shadow SNR limit**: 2 Is defined in EV levels of noise form 1 to 4 EV. The higher the SNR the less noise. | ||
==== The Advanced settings ==== | ==== The Advanced settings ==== | ||
- | **tbd** | + | {{: |
- | ==== Feedback ==== | + | **Exposure Target**: A general exposure target for the scene, |
- | If you want more visual feedback as to what's going on, enable histograms | + | **Link to Canon shutter**: |
- | In the Overlay Tab you can scroll down to Histogram | + | **Link to DUAL ISO**: ON or OFF. |
- | RAW EV indicator: OFF Here you can press the set button and select ETTR hint. This will display in the RAW histogram a hint of how many more EVs you can expose | + | Note: If Link to DUAL ISO is set to OFF, the module |
- | Also in the Overlay Tab you can scroll to Zebras, press Q, and make sure that RAW zebras are ON. The RAW zebras will show on the image itself to mark the areas where a color channel may be overblown. | + | **Show debug info**: |
- | --------------------- | + | ==== Visual Feedback ==== |
- | ===== Usage ===== | + | If you want more visual feedback to see how the image is (and you will need it for **Always on** and **Auto snap**), enable histograms and raw zebras: |
- | ETTR in RAW images | + | In the **Overlay Tab**, first make sure **Global Draw** is: **On, all modes**. |
- | If you do not have ML installed in your camera go here: | + | Then in the **Overlay Tab** you scroll down to **Histogram** |
- | RAW video & ML -- Beginners Guide and FAQ -- READ FIRST | + | |
- | http:// | + | |
- | 1. Go to Canon Menu a set Image Review: hold (This gives you a change to review | + | **RAW EV indicator**: OFF Here you can press the set button and select **ETTR hint**. |
- | 2. Put the camera in manual M mode or Av mode (it makes no difference | + | Also in the **Overlay Tab** you can scroll to **Zebras**, press **Q**, and make sure that **RAW zebras** are ON. The **RAW zebras** will show on the image itself to mark the areas where a color channel may be overblown. |
+ | |||
+ | |||
+ | |||
+ | ===== Setting it up ===== | ||
+ | |||
+ | ETTR in RAW images | ||
+ | |||
+ | 1. Go to Canon Menu and set Image Review: hold (This gives you a change to review the RAW histogram until you press half shutter to stop the preview, 2 sec is too quick to analyze the histogram but you can set it as desired NO LESS THAN 2 SEC! | ||
+ | |||
+ | 2. Put the camera in manual M mode or Av mode (either one since you must the aperture yourself), and set ISO to any number except in Auto. It wont work in auto! | ||
3. Press trash button to enter ML menu. | 3. Press trash button to enter ML menu. | ||
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4. Go to the Expo Tab and enable Auto ETTR by pressing set. | 4. Go to the Expo Tab and enable Auto ETTR by pressing set. | ||
- | 5. Press Q if you want to change ETTR details. | + | 5. Press **Q** if you want to change ETTR details. |
6. (optional) enable Global Draw | 6. (optional) enable Global Draw | ||
- | 6.1 Press Q and move to Overlay Tab. Make sure Global Draw in: On, all modes. | + | 6.1 Press **Q** and move to Overlay Tab. Make sure Global Draw in: On, all modes. |
7. (optional) enable Zebras | 7. (optional) enable Zebras | ||
- | 7.1 Scroll to Zebras, press Q, scroll to the bottom and select Use RAW zebras ON. | + | 7.1 Scroll to Zebras, press **Q**, scroll to the bottom and select Use RAW zebras ON. |
- | 7.2 Press Q | + | 7.2 Press **Q** |
8. (optional) enable the Histogram | 8. (optional) enable the Histogram | ||
- | 8.1 Scroll to Histogram and press Q | + | 8.1 Scroll to Histogram and press **Q** |
8.2. (optional) Scroll to RAW EV indicator and select ETTR hint by pressing set. | 8.2. (optional) Scroll to RAW EV indicator and select ETTR hint by pressing set. | ||
- | 8.3. Press Q | + | 8.3. Press **Q** |
12. Press trash button to exit ML menu. | 12. Press trash button to exit ML menu. | ||
- | 13. Frame you subject and set the aperture and shoot a test photo. | + | ===== Usage ===== |
- | 14. Now look at the display | + | You are highly recommended to use a tri-pod or other support. |
- | The new important features that you are looking in the display are: | + | ==== Always On mode ==== |
- | RAW histogram on the bottom right is a small graph. | + | 1. Frame you subject and set the aperture (for the DOF) and shoot a test photo. |
- | a. Inside this histogram | + | 2. Now look at the display and you should |
- | b. Inside | + | |
- | c. If there are overexposed areas you will see RAW Zebras | + | |
- | 13. Take another picture without changing the scene and you will see how the camera settings are adjusted to meet the ETTR requirements. | + | 3. Shoot another a photo and repeat to step 2 until your photo is not over exposed (few or no zebra lines, and the exposure curve up to the right side of the graph). |
+ | |||
+ | ==== Auto snap mode ==== | ||
+ | |||
+ | 1. Frame you subject and set the aperture (for the DOF). | ||
+ | |||
+ | 2. Press the shutter. | ||
+ | |||
+ | 3. Now look at the display and you should see the second image with the histogram and the zebras in the over exposed areas (if you enabled them). | ||
+ | |||
+ | ==== Press Set and HalfS DblClick modes ==== | ||
+ | |||
+ | 1. Frame you subject and set the aperture (for the DOF). | ||
+ | |||
+ | 2. Press the Set button or quickly half-press the shutter release twice depending on the mode. | ||
+ | |||
+ | 3. The camera will go into live view mode and will step through a series of exposures trying to find the proper exposure for the scene and then the camera will go out of live view mode. | ||
+ | |||
+ | 4. Do not recompose your shot. Shoot the scene. | ||
+ | |||
+ | ==== Using the histogram ==== | ||
+ | |||
+ | Inside this histogram you may see near the top-left of the graph, in white lettering, the letter E followed by a number which represents how far you can go, in EV numbers, to reach ETTR, i.e E1.2 | ||
+ | |||
+ | Inside the RAW histogram near the bottom you may see colored circles with numbers inside which represent the overblown channels (R, G, B) and the number of EV of over-exposure. | ||
+ | |||
+ | If there are overexposed areas you will see RAW Zebras in the color which is overblown. | ||
+ | |||
+ | Take another picture without changing the scene and you will see how the camera settings are adjusted to meet the ETTR requirements. | ||
If the camera beeps it means that the photo is out of specs and you should shoot again. | If the camera beeps it means that the photo is out of specs and you should shoot again. | ||
+ | |||
+ | ===== Convergence to results ===== | ||
+ | |||
+ | With the **Always on** and **Auto snap** setting which takes images, it may require at least two images (sometimes three or four) to come up with the proper exposure. | ||
+ | |||
+ | When the algorithm cannot find an adequate exposure it will beep twice and give you a message in the LCD screen. ETTR: expo limits reached, indicating the ISO and speed limits used. | ||
+ | |||
+ | When the algorithm finds an adequate exposure it will beep once and give you a message in the LCD screen. ETTR settled at ISO xxx and the shutter speed. | ||
+ | Note: the image review time in the LCD is set via Canon menu in Image Review. | ||
+ | |||
+ | ===== Raw histogram use ===== | ||
+ | |||
+ | It is best to enable RAW Histograms via Global draw. This will put a little histogram on the LCD during image review. | ||
+ | |||
+ | If you also enabled RAW zebras via Global draw, you will also see, if any, areas of the image are over-exposed. | ||
+ | |||
+ | ===== References ===== | ||
+ | |||
+ | * http:// | ||
+ | * http:// | ||
+ | * http:// |
playground/playground.txt · Last modified: 2022/05/13 16:55 by WBOX4