Chapter 01: Introduction

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Light rays do not exist!

Optics for Career Changers

Dipl. Math. Michael Schäfer
Lensation GmbH, Karlsruhe



Why this title?

In a book on optics I stumbled across this very sentence. At the time I was (still) 100% sure that there “obviously” are rays of light, so I was “a little” surprised.

My passion for collecting such “pseudo-knowledge” (things we “know” about optics and we are “sure of” – but which surprisingly don’t apply generally) was aroused. So be excited ..

Why this book?

Working in industrial image processing since 1988, I was looking 2003 for information about optics.

I was immediately faced with a problem: There are on the one hand school books, they briefly write about the topic of optics and mention nothing about practical issues. On the other hand, there are immensely expensive formula stuffed highly scientific papers that treat the even the smallest details of optics.

A practical introduction I simply could not find. This book attempts to fill this gap … and is intended to be fun and interesting. According to this, the style of the book is rather “easy goging”.
I was also newcomer to optics, so I still remember the topics that astounded me.

As mentioned, I worked since 1988 in the field of machine vision market (software development, project solutions, sales) 
 and in retrospect am “surprised” at how little knowledge about optics I had in all the time.

After all, (with sufficient range of lenses) you could try everything fast.

Big thanks go out to business friends and customers of the Lensation GmbH, which have repeatedly approached me with interesting questions.
Many of the question I at first could not answer immediately, but one grows at ones tasks …

Some of the questions are again listed here with detailed answers.

For whom is this book?

As mentioned, for career changers: 
 employees of companies that are new to image processing and optics and want/need to get a general idea about practical optics and do not want to get “too much baggage”.
People who do not want to make optics a “science” and therefore also do not have the time for an intense preoccupation with the subject. Generally include people from industrial image processessing and surveillance technology, for clients and not just the project engineers who have to deal with a project.
Also purchasers, who want to know why one optics is (actually) more expensive than another, and sales people who have to select the appropriate (optimum priced) lens for an application.
Students of image processing can also be sure to avoid one or another obstacle of practical optics.

A large list of apparent “common facts” on optics shall encourage you to spend a “short time” to check your own knowledge on the subject.
I assume that it is not known that the majority of apparent facts listed there are not generally valid.

For whom is this book not?

Physicists or people who professionally design lenses, certainly don’t need the book – but are happily invited to make me aware of errors on my part. Errors will be corrected immediately, of course.

About the Author


After my school days I graduated in mathematics in Karlsruhe. As part of a student job I came for the first time in touch with the industrial image processing about end of 1988. Dry dusty theory was suddenly replaced by exciting practice.

Even at school and university, I was happy to tutor.
Learning is quite fun when the teacher does the reference to the real life, enabling the student to see that they actually can use what they have learned.

My first contact with the image processing was as “Project Engineer”, during periods when the image processing VME bus computer systems still were – by then significantly faster and larger than PCs. When “sales” sold a project to a customer, our task was to find out what the customer really needed and then develop the appropriate programs.

In house I helt trainings about image processing regularly, later got the opportunity to change to the sales department, but enthusiasm for training and programming never left me. Since about 1990 I’m in sales and in so many years one or the other customers have some questions …
In 1996 I change to the manufacturer of the first industrial grade Smart Camera, where I was sales manager for about 8 years. Here, too, a large part of the time was spend in educating customers in a at that time completely new technology and minimalist way of programming.

About Lensation GmbH

In 2003 I founded my company (“Lensation Michael Schaefer”).
When you start a company, you often believe that it’s good to have as many legs as possible to stand on, and so initially optics, lighting, programming and also smart cameras were on board.
The first objective customers were due to favorable sources found in China soon. But I could not really make living from it, so programming was the main topic. But whoever is in programming, knows the problems: time pressure, and above all the troubleshooting makes planning in other areas completely impossible.

In 2005, I got to know (on the recommendation) my current business partner Ms.MiJung Oh and 2006 we decided to establish a joint GmbH (= the German version of a Ltd.)
The so difficult to plan programming business was abandoned, same as the smart camera business and both companies now dealt almost exclusively with optics (as well as some custom-made designs in the area of ​​optics / lighting).

By 2008, “Lensation Michael Schaefer” focused on miniature lenses and Lensation GmbH on industrial standard lenses (c-mount, telecentric, glass lenses)

Since 2009, the Lensation GmbH carries both lines of business.

The self-imposed task of Lensation GmbH can be found in two of our mottos: 
 “Hot Lenses, cool prices” and “Millions of Pixels, thousands of Lenses – one stop”

We “collect” ,so to say, excellent solutions in the field of lenses in our portfolio.

Lensation is different

  • We are not an online store, but instead offer detailed and free advice on optics and image processing, even problem solving – sometimes even to the patent :)
  • We are not just an exclusive distributor, and therefore not bound by a single lens range.
  • We are not a multi-distributor, we do not bind ourselves to well-known manufacturers.
  • We are not just manufacturers and thus we have a much larger selection and renewal rate than any individual manufacturer
  • We supply optical components and assemblies to leading lens manufacturers
  • We do contract manufacturing (for customers that come with finished lens designs)
  • We do lens design (if there is nothing suitable on the market)
  • We search the market  (=free service) for the best lenses for your project
  • We see our “competitors” rather as suppliers

In summary:

You as our customer are paramount.

Whatever is needed – be it optical components, a solution for a problem, standard products at very good prices, plastic accessories for optics or be it an introduction seminar about optics .. whatever we can do, we will do for you.

We have what you are missing – time for the lens search

When Lensation was founded, some thought “Another objective provider? Who needs that?”.

But more and more people learn to appreciate our service: Call us (phone number on website or write ( and specify the visual task that shall be solved.
That’s all .. and you can concentrate on other things around your project now…

Do not worry about the price: Apart from the fact that our experience has shown that our prices are lower than those of competitors, you may also specify in the optical parameters for the objective … and the price can be a parameter!
Further down you will find a list of information we need to know to search the optics for your task and to support you optimally.

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