What is a LUT?
A LUT is a “Look Up Table” and can be used in many ways, including changing the color or brightness of a video image, and to convert from a Log image to another type, such as a Rec. 709 image.
Throughout the world, the color standard used for broadcast is “Recommendation 709”, commonly known as “Rec. 709”. But, Rec. 709 has a limited dynamic range, just over 6 stops. Most modern cameras can record higher dynamic range, far greater that 6 stops. For film work, this higher dynamic range needs to be preserved, and the image may be recorded using a Logarithmic encoding scheme, thus the term “Log” footage.
Log images are low in contrast (typically) and can look “milky”. A “Log to Rec.709” LUT may be used to create normal Rec. 709 image with normal contrast for monitoring while recording the higher dynamic range images for post. In many cases, a Director of Photography or Cinematographer will create a special “look” for a project. This “Look” may be one with highly saturated colors or dark images for another type of project. Custom 3D LUT’s may be used to create above “looks”, as well as may other types of “looks”.
The Odyssey7Q, Odyssey7Q+ and Apollo allow you to use the 25 Preset LUT’s that we provide, while providing you with the ability to load approximately 140 more custom 3D LUT’s for use as needed.
But, most importantly, one can use our LUT support to apply a custom 3D LUT in the field, to see precisely what a scene will look like in Post. The Odyssey7Q/Odyssey7Q+ and Apollo have very accurate OLED panels and a very accurate LUT facility that allows you to apply the same LUT that you will use in Post. This allows the Director of Photography or Cinematographer to make important image decisions while shooting. Thus, one can fine-tune the images, knowing that the important details are being preserved in the images for Post.
Decoding Convergent Design LUTs
Decoding the naming convention, you get the following:
- Sony is for Sony cameras
- EE means Extended and Extended Output (using ARRI LUT nomenclature)
- SL2 is for S-Log 2 source
- L709A is an ARRI style LUT
- “-2” means that resulting image will be “Printed Down” two stops
This LUT converts S-Log 2 to Rec709 and allows over-exposure in the camera by two stops, while seeing a normal Rec709iImage on the Odyssey OLED monitor. In this example, over-exposing allows you to see a normal, properly exposed image on the monitor while recording the image in such a way that greatly reduces the noise in the image.
Using the LUT System on Odyssey & Apollo
When using the Convergent Design LUT system, it is extremely easy to select one of our Preset LUT’s. Using the touch screen interface, simply select the desired LUT.
Odyssey7Q, Odyssey7Q+, and Apollo have the most comprehensive LUT Routing System of any camera-mountable field monitor. LUT Routing gives you the ability to apply a LUT, or not, individually to each of the following:
- SDI A Output
- SDI B Output
- HDMI Output
- Image Analysis Tools
When working with a Log Image such as S-Log, S-Log 2, S-Log 3, LogC, Clog, and others, an experienced cinematographer can “read” a log image and see if the necessary detail is in the shadows, mid-range, and highlights.
While a DOP or Cinematopher will want to see images in Log to identify detail in shadow for recording purposes, it is desireable to show a client an image that is pleasing to him or her, therefore an output to a client monitor may have the LUT applied to that output. For example, with the Odyssey or Apollo it is very easy to have the following scenerio:
- Log image or a Rec. 709 image on the OLED Monitor
- LOG applied to the image analysis tools or not
- LOG image on a second monitor for the cinematographer (SDI A Out)
- Rec. 709 Image for the client (SDI B out)
- Another image, as desired, on another monitor using the HDMI output (HDMI Out)
TIP: Viewing a Rec. 709 image, while viewing a Log Image on the Waveform Monitor or RGB Parade is very useful. Exposure in stops is easier to evaluate in Log.
A brief press and hold on the LUT button opens a dialog box where “Customize Outputs” can be selected. You may then select, for each output: LUT Off, LUT On, or Mirror OLED (LUT & Overlays).
When "Mirror OLED (LUT & Overlays)" is enabled, the image on the OLED Panel will be duplicated on the selected output. If the LUT is applied on the OLED Panel, it will be applied to the external monitor(s). If an image analysis tool, such as focus assist, zebras, waveform monitor, color vectorscope, etc.) is shown on the OLED Panel, then it will also be shown on the external monitor(s).
When working with the sophisticated Image Analysis Tools built into the Odyssey or Apollo, one may want to see the tool, “Pre-LUT” (before the LUT is applied) or “Post-LUT” after the LUT has been applied. Since the LUT adjusts the image, and thus modifies the images numerical values, one may want to check the Image Analysis Tool values, before the LUT is applied. This is especially true when one uses a LUT that removes one or more stops from the exposure of an image.
To view the Image Analysis Tools “Pre-LUT”, select LUT Off for Monitoring Tools. To view the Image Analysis Tools “Post-LUT”, select LUT On for Monitoring Tools. For sophisticated users that want to see Pre-LUT or Post-LUT at will, select “Mirror OLED (LUT)”. The LUT will be applied (active) if the LUT is applied to the OLED panel. Thus, if the LUT button is Green; then the LUT will be applied (active). Also, if the LUT is being applied to the Image Analysis Tools (active) you will see a green line through those buttons.
Watch: Odyssey LUT System https://youtu.be/n9bqMqpljTg
Download LUT files and learn more: https://convergent-design.com/support.html
Watch related videos: https://convergent-design.com/videos.html
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