Lens System
The Lens System is the core structure used by Flares OFX to describe how light travels through a lens.
At its core, a lens system is a sequence of surfaces. Each surface represents a physical boundary that light passes through, such as glass, or an air. By stacking these surfaces in order, the plugin can simulate how a real-world lens behaves.
Lens systems are stored as .json files, making them portable and easy to
share. This allows lens systems to be transferred between workstations, shared
with other artists, or versioned using standard source-control tools.
What Is a Lens System?
Section titled “What Is a Lens System?”A lens system is an ordered list of lens surfaces, evaluated from front to back (from where light enters to where it exits).
- Each surface represents a physical interface (air → glass, glass → air, etc.)
- Surfaces are evaluated in sequence
- Together, they define the optical behavior of the lens
You create and manage these surfaces using the Lens System Editor.
Surfaces: The Building Blocks
Section titled “Surfaces: The Building Blocks”Each surface describes one physical boundary that light crosses. This could be:
- Air entering glass
- Glass exiting into air
- Aperture boundary
How a Single Lens Is Defined
Section titled “How a Single Lens Is Defined”A common source of confusion is that a single physical lens is made up of one surface.
Example: A Simple Glass Lens
Section titled “Example: A Simple Glass Lens”A basic lens element is defined like this:
-
Front Surface (Air → Glass)
- Describes the first curvature of the lens
- Defines how light bends as it enters the glass
- Material is set to glass
-
Back Surface (Glass → Air)
- Describes the second curvature of the lens
- Defines how light exits the glass back into air
- Material transitions back to air
Even though this is one physical lens, it requires two surfaces in the lens system.
Why Two Surfaces?
Section titled “Why Two Surfaces?”Each surface represents a change in medium. Light bends only when it crosses a boundary:
- Air → Glass (refraction occurs)
- Glass → Air (refraction occurs again)
By defining both surfaces explicitly, the lens system can accurately simulate real optical behavior.
Thinking Like an Artist
Section titled “Thinking Like an Artist”When working with lens systems, it helps to think visually:
- Each surface is a shape that light touches
- Pairs of surfaces usually form one lens element
- More surfaces = more complex optics
You can play around by modifying part of the existing lens systems, preview the result, and iterate. The Lens System Editor is designed to make experimentation fast and predictable.
Summary
Section titled “Summary”- A lens system is a sequence of surfaces
- Surfaces are created and edited in the Lens System Editor
- A single physical lens is typically defined by two surfaces
- The order and parameters of surfaces define the final look
With this mental model, you can confidently build and modify lens systems.