Let’s take a trip down memory lane.
In the mid-1990s when I was a young engineer at Optikos Corporation, I vividly remember CEO Stephen Fantone imploring my boss, Peter Carellas, to get back to work on a project Steve called, “that four-letter word!” The word in question was “book” and the book Peter was working on would become the booklet, published in 1999, “How to Measure MTF and Other Properties of Lenses,” a compilation of articles written by Optikos staff that described techniques for measuring Modulation Transfer Function (MTF) and several other lens characteristics.
Even now, more than 20 years later, the “How to Measure” (as we call it) annually still attracts hundreds of readers to optikos.com. Although most of the material in the original publication is still valid and useful, it was due for a revision; not only to update the graphics, but also to highlight recent advances in lens measurement technology.
As a veteran member of the Optikos staff, I was tasked with this project.
I enjoyed my nostalgic journey as I found bits of information to revise—a lot has changed since 1999. For example, when the original booklet was in development, camera-based video scanning methods were in their infancy—in fact Optikos pioneered this technology with the release of its VideoMTF® product in the mid-1990’s—and mechanical scanning techniques were regarded as the gold standard for accuracy and repeatability in all spectral regions. Today, video-based measurements dominate, and scanning image analyzers are only used in infrared and ultraviolet spectral bands where low-noise, uncooled, video sensors are unavailable.
While I admit I was new to the field of optics and unfamiliar with much of the material when I first read the original booklet, now, after more than 25 years of first-hand experience at Optikos, I feel that I am certainly qualified to revise and edit this document, while remaining faithful to the original publication and its authors.
We’ve also organized the material so that it resides in several easily searchable sections in our new How to Measure MTF web page, and updated a few graphs and formulas to improve readability. I hope that you like the new layout and continue to use this site as a destination for a primer on MTF and other lens measurement techniques that capture nearly 40 years of designing, manufacturing, and using Optikos® MTF measurement equipment.
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Written by Roy Youman, Optikos Corporation