“The lens does not merely capture light. It is where science learns to see and glass learns to dream.” – MJ Martin
Introduction
The making of a photographic lens is one of the quiet miracles of modern engineering. It is where physics, chemistry, mathematics, and craftsmanship meet to shape light itself. For someone deeply invested in visual storytelling through high performance systems such as my beloved Nikon mirrorless bodies, the lens is not merely an accessory. It is the true author of the image. The sensor records what the lens decides.
Where It All Begins
Lens making begins not in a machine shop but in a chemistry lab. Optical glass is not ordinary glass. It is carefully formulated from ultra pure silica blended with precise additives such as boron, lanthanum, fluorite compounds, and rare earth elements. Each additive changes how light bends when passing through the material.
The goal is to create glass with very specific refractive index and dispersion properties. Refractive index determines how strongly the glass bends light. Dispersion determines how differently it bends various wavelengths of light, which is critical for controlling colour fringing.
The raw ingredients are melted in platinum lined furnaces at temperatures exceeding 1400 degrees Celsius. During this stage, even microscopic bubbles or inconsistencies can ruin the material. The molten glass is cooled slowly over days or even weeks in a process called annealing. This relieves internal stress and ensures optical uniformity.
Designing the Path of Light
Once the optical properties of the glass are known, lens design becomes a mathematical art. Engineers build virtual optical systems that guide light from subject to sensor with minimal distortion.
A lens is made of elements and groups. An element is a single piece of shaped glass. A group is a collection of elements that move together or serve a combined optical purpose. Modern lenses may contain fifteen to twenty elements arranged into multiple groups.
Each group performs a task. Some correct spherical aberration. Others control chromatic aberration. Some flatten the field so that edges remain sharp. Others manage distortion or enhance contrast.
For a photographer using high resolution bodies such as a Nikon Z9, the importance of group design cannot be overstated. It determines whether the lens resolves fine colour detail of aircraft wings in an airshow flypast or softens it into haze.
The Secret to Lightness
Modern lenses are lighter not because glass has become lighter but because design has become smarter. Advanced computer modelling allows engineers to reduce element count while maintaining performance.
Exotic materials also play a role. Fluorite and extra low dispersion glass reduce the need for corrective elements. Aspherical elements replace several traditional curved surfaces with one precisely shaped surface that performs multiple corrections at once.
Hollow structural components made from magnesium alloys and engineered plastics reduce mechanical weight without sacrificing strength. Internal focusing systems allow only small groups to move during operation, further reducing mass.
Designing for Sharpness
Sharpness is not an accident. It is designed through control of aberrations. Engineers balance resolution and contrast by managing how light converges across the frame.
Micro contrast is enhanced by minimizing internal reflections. This is where advanced coatings become critical. Nano crystalline coatings reduce flare and ghosting, preserving edge definition even in challenging light such as sunrise aviation shoots.
Surface precision is measured in fractions of a wavelength of light. Any deviation greater than a few nanometers can soften the image.
The Influence of Focal Length
Lens design changes dramatically with focal length. Wide angle lenses must manage extreme angles of incoming light while controlling distortion. Telephoto lenses must compress distance while maintaining clarity across long optical paths.
Zoom lenses introduce complexity because multiple groups must move in coordinated ways while preserving alignment. Prime lenses, by contrast, are optimized for a single focal length and often achieve superior sharpness and simplicity.
Each focal length presents its own optical puzzle. The art of lens making lies in solving it with elegance so that the final image feels effortless, even though the science behind it is anything but.
About the Author:
Michael Martin is the Vice President of Technology with Metercor Inc., a Smart Meter, IoT, and Smart City systems integrator based in Canada. He has more than 40 years of experience in systems design for applications that use broadband networks, optical fibre, wireless, and digital communications technologies. He is a business and technology consultant. He was a senior executive consultant for 15 years with IBM, where he worked in the GBS Global Center of Competency for Energy and Utilities and the GTS Global Center of Excellence for Energy and Utilities. He is a founding partner and President of MICAN Communications and before that was President of Comlink Systems Limited and Ensat Broadcast Services, Inc., both divisions of Cygnal Technologies Corporation (CYN: TSX).
Martin served on the Board of Directors for TeraGo Inc (TGO: TSX) and on the Board of Directors for Avante Logixx Inc. (XX: TSX.V). He has served as a Member, SCC ISO-IEC JTC 1/SC-41 – Internet of Things and related technologies, ISO – International Organization for Standardization, and as a member of the NIST SP 500-325 Fog Computing Conceptual Model, National Institute of Standards and Technology. He served on the Board of Governors of the University of Ontario Institute of Technology (UOIT) [now Ontario Tech University] and on the Board of Advisers of five different Colleges in Ontario – Centennial College, Humber College, George Brown College, Durham College, Ryerson Polytechnic University [now Toronto Metropolitan University]. For 16 years he served on the Board of the Society of Motion Picture and Television Engineers (SMPTE), Toronto Section.
He holds three master’s degrees, in business (MBA), communication (MA), and education (MEd). As well, he has three undergraduate diplomas and seven certifications in business, computer programming, internetworking, project management, media, photography, and communication technology. He has completed over 60 next generation MOOC (Massive Open Online Courses) continuous education in a wide variety of topics, including: Economics, Python Programming, Internet of Things, Cloud, Artificial Intelligence and Cognitive systems, Blockchain, Agile, Big Data, Design Thinking, Security, Indigenous Canada awareness, and more.