The red line around the barrel of a Canon L-series lens depicts more than just a high level of professional image quality. It also indicates a Herculean level of human endeavour, as well as ground-breaking design and manufacturing input, particularly where the glass is concerned. As the Canon L lens timeline below shows, its development has introduced the first artificial crystal fluorite glass in a lens, high-precision aspheric lens manufacture, extra-wide apertures, unprecedented angles of view, the world's first superzoom lens and anti-reflection coatings with a structure finer than the wavelength of visible light.
You can take the performance, usability, robustness and professional quality of L lenses for granted, but what's not always so obvious is the research, precision and passion that continues to drive L-series lens development. To paraphrase Canon's words, its purpose is to "expand the possibilities of photographers with free thought, without being limited by common sense.”
The history of Canon L-series makes for fascinating reading. It's true that the scientific understanding of optics is now well established, but it would be a mistake to imagine that all the lens designs possible have now been thought of and made.
On the contrary, the pace of change is accelerating as glass makers develop new and ever more exotic materials, and new design and production processes are developed that continue to transform lens manufacturing processes. These are exciting times for lens designers and photographers alike.
1969: FL-F 300mm f/5.6
Canon's first fluorite lens
Fluorite has some terrific properties for lenses, notably the complete removal of residual chromatic aberration and the ability to shorten the total lens length. And it’s widely used in current Canon L super-telephoto lenses. However, natural fluorite contains too many impurities to be used for lens manufacturing, as large crystals can't be obtained. In 1969, Canon developed the technology to artificially 'grow' pure crystals, allowing for the production of the FL-F 300mm f/5.6, its first fluorite-based lens, and a revolutionary super-compact telephoto lens of its time.
1982: FD 14mm f/2.8L
Ultra wide-angle generated by original design tool
Ultra wide-angle lenses require complex designs and sophisticated manufacturing techniques. The FD 14mm f/2.8L was developed using an in-house design tool with an aspheric lens element to eliminate distortion, and produce the widest rectilinear prime lens in the FD range.
1989: EF 50mm f/1.0L USM
Standard lens boasting the world's largest aperture
Fast prime lenses are not a modern invention! In 1989, this lens offered the world's widest aperture for a 35mm single lens reflex camera. It was achieved using a sophisticated optical design that included two ground aspherical lenses and four high-refractive index glass lenses to produce high contrast and low lens flare even wide open at f/1.0. A floating lens construction was used to ensure image quality even at short focus distances, and the USM (UltraSonic Motor) autofocus motor offered high-speed, silent autofocus with full-time manual override.
1993: EF 35-350mm f/3.5-5.6L USM
World's first 10x zoom
This was the first 10x zoom lens for an interchangeable lens SLR and proved a powerful and versatile lens for sports photography, where speed and manoeuvrability are paramount. Designed with a six-group configuration, this lens used the fifth group for zooming, and achieved both a high zoom ratio and a compact design. Two UD (Ultra-low Dispersion) lenses provided good correction of chromatic aberration, high resolution and high contrast, and it came with an easily adjusted tripod foot.
1997: EF 300mm f/4L IS USM
First L lens with image stabiliser
Handheld telephoto photography is always a risky business for sports and wildlife photographers because of the potential for camera shake, but when Canon introduced its IS (Image Stabilisation) system for the first time on a professional lens, it offered effective shake compensation of two stops. This made handheld photography possible in situations where a tripod might otherwise have been needed, and offered photographers much more mobility. The IS unit offered two modes: Mode 1 for stationary subjects and Mode 2 for panning/tracking shots. Chromatic aberration was suppressed with two UD lenses and the lens was developed for high resolution and contrast.
2008: EF 24mm f/1.4L II USM
World's first lens with SWC (Subwavelength Structure Coating)
Lens coatings are not the most glamorous-sounding lens technology, but they are one of the most important, playing a vital part in the suppression of ghosting, flare and contrast loss. The SWC coating adopted for this lens has a structure finer than the wavelength of visible light, which was the first time this had ever been done. This minimised flare and ghosting caused by large angles of incidence, which could not be prevented with regular coatings. The EF 24mm f/1.4L also incorporated two glass moulded aspherical lenses and two UD lenses to eliminate aberrations. The SWC system was earmarked as one of Canon's key technologies for future development.
World's first Hybrid IS
Macro photography poses special problems for image stabilisation systems because it introduces a second type of potential camera movement parallel to the camera position. The solution was the EF 100mm f/2.8L Macro IS, and the first use of a new Hybrid IS system, designed to compensate for this ‘shift’ blur. In addition to a regular angular shake sensor, this lens introduced an additional acceleration sensor for movement parallel to the image plane. Data generated by the two sensors was used to drive the optical correction unit using specially-developed algorithms, and brought improved shake correction for macro photography.
First EF lens with fluorine coating
Telephoto lenses are particularly prone to picking up dust, moisture and grease on their front elements, partly because of their sheer size and partly because of the harsh outdoor environments they’re typically used in. The newly-developed fluorine coating on the EF 70-300mm f/4.5-5.6L IS USM, however, was designed to repel dirt, which could have a negative impact on image quality, and reduce the need for manual lens cleaning. The fluorocarbon coating is water- and oil-repellent, and even if dust does stick to the surface, it's easier to remove. The fluorine coating also makes it possible to wipe away finger grease, for example, without solvents.
First all-round-to-diagonal line fisheye zoom
Fisheye lenses come in two types: circular fisheyes, which create a fully circular image within the frame area, and diagonal fisheyes which fully fill the frame area with a rectangular image. Normally, if you want both types you have to buy two lenses, but in 2011 Canon launched the first lens to offer both a full 180-degree circular image to a full-frame diagonal 180-degree field of view in a single lens. Fisheye lenses are specialised tools you won't need often, so being able to carry one lens offering both types – rather than having to carry two – is a major advantage, and this lens’s operation is very simple because the frame coverage is linked to the zoom setting. At the widest focal length a circular image is produced and this enlarges to fill the frame because the zoom setting is increased, with a marker on the zoom ring showing the point where the view fills the frame.
First super-telephoto lens with a built-in extender
Teleconverters, – often known as 'extenders' – are widely used by sports and wildlife photographers to extend the reach of telephoto lenses. The gain in focal length is offset by a loss in maximum aperture, so they work best with a lens that has a wide maximum aperture to start with. The EF 200-400mm f/4L is the first super-telephoto to take this to its logical extreme and have a 1.4x converter built in. This extends its focal range to 280-560mm with a maximum aperture of f/5.6. Not only that, it can also be used with a regular EF 1.4x III extender to produce a further reach advantage up to 780mm, with an aperture of f/8 – still within the autofocus limits of cameras like the EOS-1D X II.
First lens to adopt ASC coatings to further reduce flare
ASC stands for Air Sphere Coating, a film which contains 'balls of air', which is evaporated on to the lens surface as a thin film. This strange-sounding coating provides a large reduction in flare and ghosting at light angles close to perpendicular, making it particularly suitable for telephoto lenses and their relatively narrow angles of view. The lens also makes use of one fluorite lens and one super UD lens, plus an image stabiliser unit offering four stops of shake compensation.
2015: EF 11-24mm f/4L USM
World's widest angle ultra-wide zoom
One of Canon's most spectacular ultra wide-angle lenses, the EF 11-24mm f/4L USM boasts the widest angle of view of any rectilinear (non-fisheye) lens, including primes. It makes use of some of Canon's key imaging and manufacturing technologies – including a ground aspherical lens, UD and super-UD lenses for chromatic aberration suppression, and both SWC and ASC anti-reflection lens coatings.
2015: EF 35mm f/1.4L II USM
First use of BR lens
2015 was the year of another landmark lens launch. The EF 35mm f/1.4L II USM is the first lens to use Canon's BR (Blue Spectrum Refractive Optics) lens technology, with a material that provides 'anomalous' dispersion characteristics with strong refraction of blue light (hence the name). This makes it perfect for correcting the kind of chromatic aberration found in large aperture lenses. There is high image quality from the centre to the edge of the frame, and excellent performance even wide open, allowing the unusual combination of a wide angle of view and shallow depth of field for creative background blur.
The EF 35mm f/1.4L II USM is a perfect example of how constantly evolving lens technology is not just allowing the development of more and more extreme lens designs, focal lengths and zoom ranges, but is also revolutionising the image quality of existing lens types. Wide-aperture prime lenses are not new. But the image quality now available, combined with the freedom from chromatic aberration, means that photographers can now use lenses such as the EF 35mm f/1.4L II USM at the widest aperture settings to create visual effects that would not have been possible in the past.