SIGMA – An Optical Design Legacy

The History of SIGMA Software

After many years in academia, Tina and Michael Kidger decided in 1982 to form a business based on the desktop optical design software Michael had developed for both students and professionals. Their software was named SIGMA. Its origins trace back to Michael’s student years before 1960, when he graduated from Imperial College with an MSc. After graduation, he joined Rank Taylor Hobson in Leicester, UK, where he wrote one of the world’s earliest lens optimization programs for an Elliott computer.

In 1963, Michael returned to Imperial College and joined the Optical Design Group under Charles Wynne, helping develop software for automatic lens design. Throughout the 1960s and 1970s, the team produced software for Elliott, Atlas, Mercury, IBM 709, and CDC 7000 computers. Though these early Fortran programs ran in batch mode, they were powerful and widely adopted by industry, revitalizing optical design in the UK.

By the 1970s, at Michael’s urging, the group acquired desktop computers—mostly from Hewlett-Packard—that used BASIC interpreters and supported on-screen graphics. This opened the door to interactive optical design packages. A major breakthrough came with the HP85 computer, the first truly portable system. Michael developed the first SIGMA program for the HP85, which debuted at the International Lens Design Conference in Oakland in 1980 to great interest. The success of that program led to the founding of Kidger Optics Ltd. in 1982.

During the 1980s, Kidger Optics expanded rapidly, releasing software for the HP9800 series, Apple II, IBM PC, and Macintosh platforms. With affordable hardware, optical design became accessible to engineers and scientists beyond specialized experts. This shift demanded intuitive software and new styles of training. Michael created and led international SIGMA-based courses blending theory and practice for non-specialists.

As graphical user interfaces emerged in the early 1990s, Michael oversaw the translation of SIGMA into Visual BASIC (WinSIGMA) and later into C++ for SIGMA2000 and SIGMA2100, improving speed, graphics, and compliance with Microsoft Windows standards.

In the late 1980s and early 1990s, new modules such as Illumination Analysis, Narcissus Analysis, and the Lens Library were added, and later integrated into SIGMA2000/2100. Other programs developed by Kidger Optics included SigmaTol for statistical tolerance analysis—all guided by SIGMA’s founding principles: ease of use, reliability, and simplicity. 

Kidger Optics supported and distributed Film 2000 for Professor H. Angus Macleod. 

SIGMA2100 represented the culmination of 38 years of development by Michael and his colleagues. As Michael described it, it was “the program we always wanted to have.” Development concluded in 1998 after Michael’s untimely passing during a teaching trip to Australia. The SIGMA program remains in use today, its influence enduring across the field of optical design.

All rights and source code for SIGMA, formerly owned by Kidger Optics Ltd., were acquired in 1998 by Focus Software Inc., now Zemax Development Corporation.

We acknowledge with thanks the contributions of David E. L. Freeman, MSc, DIC, student, friend, and associate of Michael J. Kidger.