Light rays do not exist!

Optics for Career Changers

Dipl. Math. Michael Schäfer
Lensation GmbH, Karlsruhe, Germany
2010-2013

Introduction

• Motivation
  Why this title?
  Why this book?
  For whom is this book?
  For whom is this book not?
• About the Author
  Background
  About Lensation GmbH
  Lensation is different
  We have what you are missing – time for lens search

Basics

• Open your eyes! Lenses are everywhere
• Lens model
• Comparison entocentrical – telecentrical – pericentrical
• There’s thousands and thousands of lenses – but why?
  Money reasons
  Project constraints
  Technical developments

Hostile Brothers

• Depth of Field vs. Aperture
• Depth of Field vs. Resolution
• Vignetting vs. Distortion
• Quality vs. price
  There’s a lower limit for the lens price
  Cost driver no. 1 : Aperture
  Cost driver distortion
  Cost driver resolution

Dangerous Half Knowledge

• Half knowledge about light
  The speed of light is constant and equal for all light colors
  Light does not change its direction within a medium.
• Half knowledge about Glass
  Glass is transparent
  Every type of glass has a different refractive index
• Half knowledge about lenses
  Lenses are transparent.
  Lenses for large sensor can also be used on all smaller sensors.
  Opening angle and focal length are equivalent.
  Lenses with the same angle, the same length and focal length have the same FOV.
  The larger the (apparent) iris of a lens, the more light sensitive it is.
  Lenses of the same focal length have the same viewing angle.
  The larger the f-number the larger the depth of field.
  A lens is the more light sensitive, the larger the apparent diameter of the iris.
  An objective can never be “too good”.
  For C-mount lenses, the distance between the flange of the lens thread and the sensor (image plane) is 17.526 mm
  For CS-mount lenses, the distance between the flange of the lens thread and the sensor (image plane) is 12.52 mm
  The length difference between the Back Flange Length of C-mount and CS-mount lens is 5mm
  Lenses change the focal length with the sensor size.
  Fixed focal length lenses have a constant magnification.
  If object and the sensor have the same aspect ratio (eg 4:3), so does the image
  Images of near objects are larger than images of remote objects.
  The physical distance between the object and the sensor determines the aperture angle.