Research | Colour ManagementMaking my own D-Cinelike>Lin LUT
August 1st, 2018
HIGH DYNAMIC RANGE, REC709, LOG, DISPLAY TRANSFORM
This of course, has the negative impact of not being truly scalable to Linear, Scene Referred colour space using Sobotka and Chambers (2018) colour transform methodologies. To this end the following video documents my decisions throughout the LUT building process, and sheds light on my approach to the capture of light/exposure information; analysing and recording 8 bit RGB values; and, the normalizing and Linearization of this same data to a 1DOSMO_to_LIN LUT (Look Up Table)
- Validity of Research 95%
- Complexity of Content 100%
- BENEFIT OF ACTIVITY 100%
Practice as Research
APPLYING PAUL CHAMBERS METHODOLOGY TO A CAMERA WITH NO APERTURE, LUT MANAGEMENT OR TRIPOD MOUNT
Even though Paul Chambers had recently proved that a mid range DSLR could capture lighting data that could be converted using Troy Sobotka’s Math, the OSMO had a lot more doubt hanging over its head. Despite its availability, low price and smoothness of movement, it has a multitude of issues that may infringe on its ability to be converted as per mid range SLR models.
For example, the basic OSMO model has no aperture control for the camera so only Shutter speed can be used to stop up or down. Manual controls can fix white balance and ISO, but the Zebras seem far from accurate following my previous tests into D-Log and C-Cinelike profiles; there is no way of mounting the camera to a tripod; and, the lens is so wide that it has noticeable barrel distortion and edge to edge luma shift issues.
To this end, in the video you will see that I not only have to create some “custom” rigging, but also apply some guest work to EV stop increments above -2 +2 stops, as the OSMO readout stops before the exposure does. Additionally, I have to trust the Histogram for exposure readings; and, lastly have to put the lens cap on the camera to ‘zero’ the exposure at black; even in D-Cinelike.
this all said, despite all of these issues, I continued with Chambers and Sobotka’s methodology and it seemed to work none the less. This is as much a celebration of the math as it is my efforts to create accurate and consistent readings that match exactly the manufacturers specification sheets for dynamic range, despite not being able to read or control – accurately – stops above or below 2.0 either side of 0.
OSMO is AWKWARD
The baseline OSMO is very awkward to use in a controlled or static environment: no tripod; not aperture; inaccurate readouts (Zebras, Histogram, EV); and, Lens Vignetting.
D-Cinelike still cannot achieve 0
D-Cinelike, despite the histogram readouts to contrary, cannot achieve pure black without capping the lens.
Shutter Speed control gives approx. 0.3/0.4 EV control per increment
Luckily, it seems that despite the fact that the EV display on camera could not display all of the exposure range I recorded, by counting in my head the number of Shutter speed increments, I was able to count back or forwards the limits of EV stop range below and above 0 EV. The math proves that this worked.
Sobotka and Chambers methodology is forgivingly powerful
Even Though my guess work was informed and seemingly accurate in the end, it also seems that Sobotka and Chambers workflow for calculating the math – once captured and measured – is very powerful indeed; converting display referred colour to a virtually linear curve.
Here are some recent posts that I have written as part of the Digital Media Practice 3 project – ‘FUSE’
September 7th, 2018 Chiefly, once the lighting is set up correctly using the Linear EXR data as an environment map, and by setting the colour management to 'Filmic' - the colour management system written and developed by Troy Sobotka - much of the heavy lifting is...
August 30th, 2018 Continuing on from my modelling process, I moved on to the texture painting process in Substance Painter. I not only chose this programme for its procedural, non-destructive, scalable workflow, but also so that I could try a separate Normal/Height...
August 24th, 2018 Following my successful shoot in The Peak District, I began the modelling process. Chiefly, I used my research from previous projects in The Arcane Welder project to combine both mesh-based and Boolean-based deformation with procedural kit bashing...