Ray-transfer imaging explorer

This interactive explorer uses a JavaScript module. Open it through a local web server to change the system. The static reference below remains valid without interaction.

Three rays leave an object point 20 millimetres above the optical axis, pass through a 100 millimetre focal-length lens, and meet 40 millimetres below the axis at a sensor 300 millimetres to the right.
At the default focused sensor plane, differently sloped paraxial rays reach the same image height.

Interactive explorer

Explore: when does a ray fan form an image?

Move the sensor relative to a thin lens. The rays start at one object point with different slopes; they form one image-plane height only when the system entry B is zero.

Fixed schematic axes: the horizontal coordinate uses a fixed −320 to +640 mm range; the transverse display is fixed at ±60 mm. Axial and transverse scales intentionally differ.

Sensor intercepts