An all-in-one zoom lens covers a wide range of focal lengths from wide angles to telephoto lengths in a single unit. With the ability to instantly switch the angle of view without having to change lenses, an all-in-one zoom is an exceptionally useful lens that provides more photo opportunities and superb portability.
When Tamron first envisaged developing a practical all-in-one zoom lens, it set a goal of creating a lens chassis as small as a cylinder with a diameter as wide as a cigarette packet. Given the conventions governing lens design at the time, this was an extremely challenging prospect. Unfazed, the design team revisited every aspect of a lens, from the selection of materials and optical systems to the design of mechanisms in each component, and in 1992, the process of trial and error culminated in the creation of the first lens in the series, the 28-200mm F/3.8-5.6 (Model 71D).
Since then, Tamron's all-in-one zoom lenses have continued to evolve based on the concept of lighter, smaller and more reasonable. The result has been a long line of innovative products that have truly redefined the conventions of lens design.
Utilizing the specialized glass materials that hold the key to high definition
It comes down to striking a balance between high zoom magnification and high image quality. Success in the mass production of compound aspherical lenses provided the way out of this vexingly difficult problem for optical design. Through the aggressive use of aspherical lenses that were still only used in a subset of specialized lenses at the time of introduction, Tamron gained the ability to effectively correct for various aberrations, such as distortion and spherical aberration. Tamron was also among the first to incorporate specialized glass elements such as LD and AD elements to deal with the chromatic aberration aspherical lenses are unable to correct, achieving sharp, clear and crisp rendering. Tamron has also developed groundbreaking technologies unique to all-in-one zoom lenses. For instance, we succeeded in making the optical system significantly more compact by placing high refractive index XR glass elements in the front group.
Further improvements to image quality tailored to digital cameras
The widespread adoption of digital cameras to take the place of film cameras has also triggered a major turning point in the optical design of all-in-one zoom lenses. From the film era when the development of all-in-one zooms began, Tamron has employed its unique BBAR coating to ensure high-contrast images by preventing optical reflection on lens surfaces. However, as digital cameras tend to be susceptible to ghosting and flaring from inner reflections caused by the image sensor itself, more advanced anti-reflection measures than had previously been employed were required. In response, Tamron's lens lineup was transformed into the Di Series of digitally oriented high-performance lenses which advanced the transmission factor of the BBAR coating and the optical design greater than before. The range has since developed into the Di Series for both film and digital cameras, the Di II Series for APS-C format digital SLR cameras and the Di III Series for mirrorless interchangeable-lens cameras as Tamron continues to enhance the rendering performance in response to the increasingly high performance of digital cameras.
High-precision technology to retract an extended lens barrel into a compact size
Tamron takes pride in its high-precision multiple-cam technologies, which make it possible to retract a long lens barrel extended to the telephoto end into a compact lens chassis at the wide end with high precision. From the outside, it appears that the lens barrel of an all-in-one zoom lens is simply extending with zooming action, but inside, multiple cams are controlling the complex movements of the lens groups associated with the extensive changes in focal length. The high-precision multiple-cam is expertly integrated with an internal focus mechanism that achieves shorter minimum focus distances and improved rendering performance (Integrated Focus Cam), and this extremely complex yet subtle precision mechanism achieves zoom control that boasts a sturdy feel. For the Model B028 ultra-telephoto all-in-one zoom lens covering an even higher telephoto range of 400mm (620mm in the 35mm format), a three-step extension lens barrel has been developed. With the cam divided into more layers than in past models, it has paved the way for smooth, stable zooming operations.
Unique mechanical design to attain comfortable operability
Given the very nature of an all-in-one zoom that fits a wide focal range into a single lens, in the course of development Tamron has continuously sought to boost functionality to ensure comfortable operation under all conditions. While boosting the corrective effects of our proprietary VC vibration compensation mechanism with optimized algorithms, we have simplified the mechanical structure to help produce a more compact lens. In a bid to achieve lens size reduction and high-speed, silent AF, the PZD has been developed. It features the world leading application of a standing wave ultrasonic motor. HLD (High/Low torque-modulated Drive) characterized by high precision and high torque has been also developed. Including DC motors that have a proven track record with all-in-one zoom and stepping motors ideal for shooting video because of their low operating noises, the AF drive systems best suited to the characteristics of the lenses are chosen.
Consistent quality control from molding to in-house production
Tamron builds all the molds used to manufacture key components of its lenses in-house, and those molds requiring particularly high levels of precision are hand-crafted by skilled craftspeople. As a result, each individual component possesses high quality, and these parts are woven together under stringently control to produce a single all-in-one zoom lens.
Embracing the proposition of "smaller and higher definition," all-in-one zoom lenses built with constant and uncompromising technological innovation are the culmination of the proprietary technologies Tamron has accumulated.