The story of Tamronís all-in-one zoom lenses begins with the Model 71D, an SLR lens introduced in 1992. This lens featured a focal length of 28-200mm and a 7.1x zoom, one of the highest among SLR lenses in those days.
Development of this lens began in 1989, nearly three years prior to its release. The assignment given to the development team was to create a lens of a size that made it easily portable. Indeed, all-in-one zoom lenses with almost the same focal length were already on the market, but they were large and heavy and delivered poor picture quality. All users (especially beginners) found them difficult to handle. And so the development team set a goal of creating a lens as small as a cylinder, with a diameter as wide as a cigarette packet. Development began with the creation of a graph-paper cylinder of that size as a reference sample.
Because the concept of an easily portable all-in-one zoom lens was without precedent, development was extremely challenging and posed many conundrums for those involved. The development team created many prototypes and tested their resolutions, until a satisfactory optical performance was obtained. Finally, they succeeded in developing a model by applying the expertise Tamron had accumulated through its extensive experience in another of its businesses: designing and manufacturing all-in-one zoom lenses for video cameras. Development also received a boost when the team was successful in mass-producing an aspherical (hybrid aspherical) lens with functions equivalent to those of multiple lenses.
The outcome of their efforts was called the Model 71D, every aspect of which incorporated Tamronís unique, creative innovations. The aspherical lenses were arranged in the positions which would permit a reduction in the number of lenses and increase design flexibility, while ensuring more effective aberration corrections. They also incorporated the Triple-Cam zoom system, which enables the cams to zoom and focus within a three-layer lens barrel, and an engineering plastic which protects the complex structure from shocks and helps reduce the weight of the product. In the production process, the optical axis tended to be tilted and uniform precision was hard to obtain. The development team solved these problems by creating methods for checking and adjusting the precision. After nearly three years of efforts, they finally completed a product that was ready to be marketed.
The Model 71D thus released first became a hit in Europe and the United States. It later became popular in Japan, as a revolutionary replacement lens. However, the development team of Tamron was not satisfied with this result, because the minimum focus distance (shortest possible distance between the lens and an object) of the Model 71D was still 2.1m. This distance was acceptable for a 200mm telephoto lens, but was unsatisfactory for a 28mm wide-angle zoom lens. Wide-angle photos need to be taken from up close to have the unique quality of exaggerated perspective. The long minimum focus distance was all the more problematic because the zoom lens was intended for shooting a variety of objects and scenes in everyday life.
In 1996, the Model 171D was released. The 171D differed markedly from its predecessor, the Model 71D, in the minimum focus distance. The distance, which was 2.1 m for the Model 71D, was suddenly shortened to 52cm, although this was available only when the lens was used at a focal length of 135mm. The maximum magnification, or the maximum size of the object on the film, increased from approx. 0.11x to approx. 0.21x, making the 171D an even more user-friendly, all-in-one zoom lens.
This upgrade was enabled by use of an alternative focusing system. The system adopted for the Model 71D was the front focus system, in which the large lens in front was moved outward as the camera approached the object. The Model 171D alternatively applied the internal focus system, which permitted focus by moving the small lens within the barrel (the length of the lens barrel remained unchanged irrespective of the shooting distance). This enabled shooting from up close without sacrificing performance. This upgrade was welcomed by camera aficionados. However, the development team was still not completely satisfied with this model, because its minimum focus distance fluctuated somewhat depending on the focal length.
The Model 371D, released in 2000, was an all-in-one zoom lens with a close-up capability that finally satisfied all members of Tamronís development team. Its minimum focus distance was 49cm, only a little shorter than before, but this distance was available throughout the entire zoom range. The maximum magnification was approx. 0.25x at the maximum focal length of 200mm. The Model 371D boasted specifications close to those of a macro lens.
Initially, the focal length of Tamronís all-in-one zoom lenses was just 28-200mm. To respond to demands from users who desired a longer focal length, Tamron released the Model 185D in 1999. The focal length of this lens was 28-300mm, with a maximum length 100 mm longer than that found in previous models. This increased the zoom to 10.7x. Although the size of this lens was slightly larger than the Model 171D and other models, the 185D was popular with users who wanted to photograph objects at longer distances. Tamronís all-in-one zoom lenses were now offered with two focal lengths, 28-200mm and 28-300mm, until the lens designed exclusively for digital still cameras was released in 2005.
In 2001, Tamron released the Model A03, the smallest and lightest lens ever. The A03 featured a filter diameter of just 62 mm, compared with 72 mm for the Model 171D. This breakthrough was achieved using Tamronís XR technology. Usually, glass material with a low refractive index is used for large lenses in the front to control aberrations. The revolutionary XR technology applies an optical design in which a glass material with a high refractive index is used for front lenses, while aberrations are eliminated by lenses in the back. Use of high refractive index lenses for the front group reduced the total optical length, which permitted significant downsizing of the lens barrel. This is how the Model A03 was created. "A lens you can bring anywhere to take everything"-the Model A03 was much closer to the ideal all-in-one zoom lens in terms of its size. It also differed entirely from previous models in exterior design, with lines that would be familiar to users of the current models. The XR technology was also incorporated into the 28-300mm models, and the Model A06 was released in 2002. At this time, SLR cameras were undergoing a revolutionary change of historic proportions.
Around 2000, digital SLR cameras, traditionally designed for professional photographers and enthusiasts, began to be available at more affordable prices. They quickly found a large market, given their excellent compatibility with digital devices such as PCs and inkjet printers. They also freed users from concerns over film and development costs. At the same time, however, digital SLR cameras had some troublesome characteristics. Unlike silver salt film cameras, the lens performance of digital SLR cameras was directly reflected in the quality of pictures taken. Above all, picture quality was susceptible to flares caused by inner reflections. The use of lenses with weak coating led immediately to lower resolutions. The so-called telecentricity, or the idea that the light should hit the image sensor as perpendicularly as possible, was considered more important than before.
Tamron subsequently released the Di series of lenses featuring optical designs and coatings optimized for the properties of digital SLR cameras. All-in-one zoom lenses were naturally included in the Di series models, and the Model A061, which was based on the Model A06, was released in 2004.
Tamron also began developing an all-in-one zoom lens dedicated for digital SLR cameras incorporating image sensors in the APS-C size (approx. 23.1 x 15.4mm) image sensors, which are slightly smaller than full-size (36 x 24mm) ones. And in 2005, Tamron released the Model A14, its first all-in-one zoom lens dedicated for digital SLR cameras. The lineup of Tamronís lenses dedicated for digital still cameras, including the Model A14, are known as the Di II series. The focal length of the Model A14 is 18-200mm. This is equivalent to 27-300mm when converted into one full-size model. Naturally, the image circle of the Di II series was also made to fit the APS-C format.
In 2006, the 28-200 mm Model A03 was replaced by the Model A031, a dedicated Di-series lens for digital SLR cameras.
In 2007, or 15 years after the release of the Model 71D, the Di II series all-in-one zoom lenses for digital SLR cameras achieved a further increase in zoom. The Model A18, with a focal length of 18-250mm, was released in this year. This model also boasted an impressive zoom of 13.9x. Surprisingly, its lens barrel was almost the same size as that of its predecessor, the Model A14, yet it weighed only 30g more.
The same year also saw the release of the Model A20, an all-in-one zoom lens equipped with built-in vibration compensation (VC) mechanism that Tamron had been developing for many years. At this time, incorporation of the VC mechanism was common among standard zoom and telephoto zoom lenses. The Model A20 was a Di-series lens compatible with full-size digital SLR cameras. Its focal length was 28-300mm. While its lens barrel was slightly larger and heavier than the previous model, it was superior to other models in that it delivered vibration compensation effects equivalent to about four steps in shutter speed. In addition, the Tamron-exclusive three-coil system delivered a superb VC effect. It ensured stable viewfinder images, which looked as if they were pasted to the finder. Many users were captivated by this groundbreaking intra-lens VC mechanism.
It was not long before the VC mechanism was also incorporated in the Di II series all-in-one zoom lenses exclusively for APS-C digital SLR cameras. In 2008, the Model B003 was released. In addition to incorporating the VC mechanism, the Model B003 had a focal length of 18-270mm, with the maximum length exceeding that of the A18, and a zoom of 15x. The weight of the lens barrel increased with the incorporation of the VC mechanism, yet it was still comfortable to use thanks to the VC.
A DC motor has traditionally been built into the AF unit of Tamronís all-in-one zoom lenses. The DC motor is extremely cost-efficient and incorporates mature control technologies, eliminating virtually all possible practical issues associated with operations. However, the motor was sometimes felt to be too noisy. In response, Tamron started to develop an all-in-one zoom lens with a completely new actuator (motor), which uses piezo elements to drive the AF unit. This new motor makes use of the properties of piezo elements, which change in shape when impressed, and represents a major contribution to the silent movement of the AF unit. The driving unit is also compact and can be housed in the lens barrel, where it occupies little space. Tamron also sought to downsize the VC mechanism. The result was the Model B008, an all-in-one zoom lens exclusively for digital SLR cameras.
Model B008 comes in a compact size close to that of Model A18. This is enabled by the use of the piezo motor and downsized VC unit. The size also fits entry-class digital SLR cameras. The AF unit, silently driven by the piezo motor, creates the sensation that there is no lens, making the Model B008 even closer to an ideal all-in-one zoom lens that allows you to shoot photos naturally.
Tamronís all-in-one zoom lenses have been evolving constantly for more than 20 years since the development of the Model 71D, the first lens of its kind. With a reputation as a pioneer of all-in-one zoom lenses, Tamron has consistently offered a lineup of challenging products. The Model B008 has earned its place in this lineup.