Distance between the object side principal point and the object.

For larger distances, this is about the working distance

# Archives

# Object to image distance

# OPL

# optical axis

The symmetry axis of a lens or a lens system.

# optical magnification

May the width of an object be 1.6mm and the sensor width = 4.8mm

Then

Then

May the width of an object be 36mm and the sensor width = 3.6mm

Then

Then

# Optical Path Length

The optical path length is proportional to the time light needs to travel between two points

In a homogenous medium with refractuion index n and physical point distance d this formula simplifies to

# Optimal Aperture

# orthographic

orthographic lenses are a type of fisheye lenses

**orthographic**lenses are also called”

**hemispherical**“or “

**orthographisch**”

**orthographic**lenses use an image mapping function of type

maintains planar illuminance

weak | medium | strong | max |
---|---|---|---|

66 | 90 | 120 | 180 |

An orthographic / hemispherical fisheye, uses a parallel projection of a hemisphere onto a plane. The resulting image will obviously be circular. The widest view angle is 180 degrees. At +/-90 degrees extreme distortion will occur. Due to this heavy distortion it’s less often used than f-Theta / angular fisheye.

see:

fisheye types