Stretch
- Max Austin
- Jan 10, 2021
- 1 min read
Updated: Jan 31, 2021
An ST Map based lens distortion Gizmo for artists.
Quick Overview:
In Depth Look:
Reference Research & Reading
Gathering reference is always the first and arguably the most important part of my process, here are a few of the resources I used.
https://photographylife.com/what-is-distortion
https://expertphotography.com/what-is-lens-distortion/
https://www.masterclass.com/articles/what-is-lens-distortion-in-photography#what-is-pincushion-distortion
There are two main types of lens distortion, barrel and pincushion as seen below.
I also knew that I wanted to incorporate a little bit of chromatic ab so I gathered some reference for what that would look like (I have plans to build a more comprehensive chromatic AB tool next).
My first instinct was to use expressions to warp the ST map itself. Below is a test I started using the Nuke if statement syntax. I abandoned it quite early on because I realized that distortion couldn't be calculated linearly.
Another very different attempt had me using a series of cornerpins procedurally mapped to each quadrant of the image. While this wasn't a complete failure it was time consuming and I may circle back to it later for further testing.
The method I ended up using was a simple transformation of the ST Map that when used would resemble distortion.
Not exactly the complex monster I thought I would end up with but I was reminded of an acronym I learned in jazz band: KISS [Keep It Simple, Stupid]
The distortion was linked to the UI with a blur to control softness. There's a switch node that's connected to the checkbox in the UI dictating whether the distortion will also offset the RGB channels or not.
When it's checked the R/GB channels are set to add/subtract a value to those channels creating aberration that it also now tied to the distortion amount.
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