production – Page 20

lighting, production

HDRI math with cubemaps

pIXELsHAM.com

Jan 12, 2021

www.paul-reed.co.uk/programming.html

blender, production, software

Blender Universal human face rig

pIXELsHAM.com

Jan 9, 2021

gumroad.com/l/dOumo

Watch this video on YouTube

Watch this video on YouTube

lighting, photography, production

HDRI shooting and editing by Xuan Prada and Greg Zaal

pIXELsHAM.com

Jan 8, 2021

www.xuanprada.com/blog/2014/11/3/hdri-shooting

http://blog.gregzaal.com/2016/03/16/make-your-own-hdri/

http://blog.hdrihaven.com/how-to-create-high-quality-hdri/

Shooting checklist

Full coverage of the scene (fish-eye shots)
Backplates for look-development (including ground or floor)
Macbeth chart for white balance
Grey ball for lighting calibration
Chrome ball for lighting orientation
Basic scene measurements
Material samples
Individual HDR artificial lighting sources if required

Methodology

Plant the tripod where the action happens, stabilise it and level it
Set manual focus
Set white balance
Set ISO
Set raw+jpg
Set apperture
Metering exposure
Set neutral exposure
Read histogram and adjust neutral exposure if necessary
Shot slate (operator name, location, date, time, project code name, etc)
Set auto bracketing
Shot 5 to 7 exposures with 3 stops difference covering the whole environment
Place the aromatic kit where the tripod was placed, and take 3 exposures. Keep half of the grey sphere hit by the sun and half in shade.
Place the Macbeth chart 1m away from tripod on the floor and take 3 exposures
Take backplates and ground/floor texture references
Shoot reference materials
Write down measurements of the scene, specially if you are shooting interiors.
If shooting artificial lights take HDR samples of each individual lighting source.

Exposures starting point

Day light sun visible ISO 100 F22
Day light sun hidden ISO 100 F16
Cloudy ISO 320 F16
Sunrise/Sunset ISO 100 F11
Interior well lit ISO 320 F16
Interior ambient bright ISO 320 F10
Interior bad light ISO 640 F10
Interior ambient dark ISO 640 F8
Low light situation ISO 640 F5

NOTE: The goal is to clean the initial individual brackets before or at merging time as much as possible.
This means:

keeping original shooting metadata
de-fringing
removing aberration (through camera lens data or automatically)
at 32 bit
in ACEScg (or ACES) wherever possible

Here are the tips for using the chromatic ball in VFX projects, written in English:
https://www.linkedin.com/posts/bellrodrigo_here-are-the-tips-for-using-the-chromatic-activity-7200950595438940160-AGBp

Tips for Using the Chromatic Ball in VFX Projects**

The chromatic ball is an invaluable tool in VFX work, helping to capture lighting and reflection data crucial for integrating CGI elements seamlessly. Here are some tips to maximize its effectiveness:

1. **Positioning**:
– Place the chromatic ball in the same lighting conditions as the main subject. Ensure it is visible in the camera frame but not obstructing the main action.
– Ideally, place the ball where the CGI elements will be integrated to match the lighting and reflections accurately.

2. **Recording Reference Footage**:
– Capture reference footage of the chromatic ball at the beginning and end of each scene or lighting setup. This ensures you have consistent lighting data for the entire shoot.

3. **Consistent Angles**:
– Use consistent camera angles and heights when recording the chromatic ball. This helps in comparing and matching lighting setups across different shots.

4. **Combine with a Gray Ball**:
– Use a gray ball alongside the chromatic ball. The gray ball provides a neutral reference for exposure and color balance, complementing the chromatic ball’s reflection data.

5. **Marking Positions**:
– Mark the position of the chromatic ball on the set to ensure consistency when shooting multiple takes or different camera angles.

6. **Lighting Analysis**:
– Analyze the chromatic ball footage to understand the light sources, intensity, direction, and color temperature. This information is crucial for creating realistic CGI lighting and shadows.

7. **Reflection Analysis**:
– Use the chromatic ball to capture the environment’s reflections. This helps in accurately reflecting the CGI elements within the same scene, making them blend seamlessly.

8. **Use HDRI**:
– Capture High Dynamic Range Imagery (HDRI) of the chromatic ball. HDRI provides detailed lighting information and can be used to light CGI scenes with greater realism.

9. **Communication with VFX Team**:
– Ensure that the VFX team is aware of the chromatic ball’s data and how it was captured. Clear communication ensures that the data is used effectively in post-production.

10. **Post-Production Adjustments**:
– In post-production, use the chromatic ball data to adjust the CGI elements’ lighting and reflections. This ensures that the final output is visually cohesive and realistic.