Forced Perspective

The Forced Perspective calculator computes the angle based on the height of the object and distance to the object.

INSTRUCTIONS: Choose units and enter the following:

• (h) Height of Object
• (D) Distance to Object

The Math / Science

The formula for force perspective is:

`Θ = 2 tan^(-1)(h/(2D))`

where:

• Θ is the forced perspective angle
• h is the height of the object
• D is the distance to the object

Forced perspective is a photography technique that creates an optical illusion by making objects appear larger, smaller, closer, or farther away than they actually are. This is achieved by carefully positioning the camera, subject, and background to manipulate depth perception.

How It Works:

• Distance & Positioning: Placing a subject closer to the camera makes it appear larger, while placing it farther away makes it look smaller.
• Angle & Framing: Adjusting the camera angle can enhance or distort the effect.
• Depth Cues: Minimizing depth perception cues (like shadows and overlapping objects) can make the illusion more convincing.

Common Examples:

• A person appearing to "hold" the sun or moon.
• A tourist "pinching" the top of the Eiffel Tower.
• A person standing far away appearing to fit inside a small cup in the foreground.
• Movie effects that make actors look tiny or gigantic without CGI (e.g., The Lord of the Rings used forced perspective to make Hobbits look smaller than humans).

This is the formula for calculation angular size,  where θ is the subtended angle, h is the actual size of the object and D is the distance from the lens to the object.

Source: Wikipedia
https://en.wikipedia.org/wiki/Forced_perspective