Innovation In the pursuit of optical excellence
For well over half a century Tamron has been recognised as a leading innovator in cutting-edge optical design, and acclaimed for its mastery of the underlying mechanical and electronic technologies that make today's amazing lenses possible. Developing practical, compact, easy-to-use lightweight zoom lenses with incredible zoom ranges, apertures and close focusing ability, that also deliver world-class imaging performance, is not simply a matter of refining existing ideas — it entails creative thinking at the highest level.
Here is a definitive list of the design concepts used in today's state-of-the-art Tamron lenses.
Extra Refractive Index
More compact lenses with superior image quality
XR (Extra Refractive Index) glass can bend light rays at steeper angles, thereby decreasing the physical length of the lens while enhancing imaging performance by minimising optical aberrations. With its superior light-bending power, XR glass makes it possible to design a short-barrel lens with the same light-gathering ability (aperture value) as a long-barrel lens – even with a smaller lens diameter. By using this principle Tamron has been able to shorten the length of the entire optical system and produce lighter, more compact lenses of the same speed, and also to provide greater zoom ranges in lenses that are much more convenient to carry and hand-hold.
XR glass is costlier than conventional glass but it yields enhanced optical power distribution, making the innovative XR lens designs possible.
Far superior image quality – while reducing lens size and weight
Tamron uses several hybrid aspherical lens elements in its lenses bearing the Aspherical designation. The benefits are two-fold: first, their non-spherical shapes virtually eliminate spherical aberration and image distortion. Second, as one hybrid aspherical lens element can take the place of multiple elements without compromising performance, they allow the lens to be much more compact.
As a result, these innovative optics have played a crucial role in delivering uniformly high image quality across all apertures and focal lengths of extraordinarily compact ultra-zoom lenses.
Sharpens edges by reducing 'colour fringing'
Chromatic aberration occurs when a lens element refracts different wavelengths of a ray of light – its rainbow colours – at very slightly different angles. This results in the 'colour fringing' that reduces the sharpness of an image. LD elements are made from special glass materials with extremely low dispersion indices (i.e. the refraction of a ray of light into rainbow colours is extremely narrow). Thus they effectively compensate for chromatic aberration at the centre of the field (on axis), a particular problem at long focal lengths (the telephoto end of the zoom range), and for lateral chromatic aberration (toward the edges of the field) that often occurs at short (wideangle) focal lengths.
Although costly, LD glass materials result in clear, vivid image quality.
Controls the dispersion of specific wavelengths of light
AD glass is a special type of optical glass that is used to achieve more precise control of chromatic aberrations, thereby enhancing overall imaging performance. Glass of this type provides an abnormally large partial dispersion ratio (amount of diffraction) for light of specific wavelength ranges (colours) within the visible spectrum. By combining AD glass having these special characteristics with elements made of normal glass having different dispersion characteristics, it is possible to control the dispersion factors of a specific wavelength.
This enhanced level of control results much lower levels of on-axis (central) chromatic aberration for telephoto lenses (or zooms used at telephoto settings) and a significant reduction of lateral (peripheral) chromatic aberration for wide-angle lenses (or zooms used at wideangle settings).
Like LD glass, AD glass material is costly but provides clear, vivid image quality.
XLDExtra Low Dispersion
Dispersive properties even lower than LD elements
Extra Low Dispersion lens elements are made from a special high-grade glass that has dispersive properties (i.e. where refraction causes the dispersion of white light into spectral hues) even lower than standard LD lenses, in fact being similar to those of fluorite. In combination with LD elements, these make for an optimal optical design that delivers superb resolution with advanced correction of axial chromatic and magnification aberrations – major inhibitors of image quality.
The result is a lens that delivers sharp contrast and better descriptive performance throughout the entire zoom range.
HIDHigh Index High Dispersion
Minimises chromatic aberrations
The use of HID glass elements in a lens minimises on-axis and lateral chromatic aberrations that are the greatest hindrances to achieving high image quality. HID glass has allowed Tamron to produce complex lenses such as long-range zooms that are conveniently compact and lightweight while delivering outstanding performance.
Advanced lens coating produces even sharper, crisper images
This new coating technique developed by Tamron deploys a nano-structured* layer with dimensions smaller than the wavelengths of visible rays of light. Called eBAND (extended Bandwidth & ANgular-Dependency), its ultra-low refractive index, combined with the sophisticated multiple-layer coatings underneath, yields significant anti-reflection properties, absolutely minimising flare and ghosting to deliver sharp, crisp images.
*1nm = 1/1,000,000mm
Broad-Band Anti-Reflective coating
Cleaner, crisper images without flare or ghosting
Tamron uses advanced multi-coating techniques to suppress reflections and light dispersion on lens element surfaces that result in reduced light transmission and may, under adverse conditions, cause flare and ghost images that reduce contrast and can diminish image quality. The BBAR multiple-layer coating technique also helps to provide the best possible colour balance for vibrant and accurate colour rendition. Tamron has developed an improved proprietary version of BBAR multi-coating that successfully increases light transmission in both longer and shorter wavelengths, and has applied it to all the latest Tamron lenses.
Super Performance series
Performance takes priority for superb image quality
This line of ultra-high-performance lenses is designed and manufactured to the exacting specifications demanded by professionals and others who require the highest possible image quality. The foremost priority is achieving superior performance parameters – high design standards take priority over cost constraints. As a result, Tamron SP lenses feature innovative designs that have established an enviable reputation for excellence amongst demanding photographers.
Compensates for camera blur on long shutter speeds – for sharp images in much lower light
Tamron's unique VC mechanism uses a proprietary actuator and algorithms to deliver an extremely stable viewfinder image with excellent tracking. The mechanism employs a tri-axial system in which three driving coils move internal optical components within the VC lens electromagnetically. The VC lens elements are held in place only by contact with three ball bearings – which in the latest Tamron VC lenses are ceramic – achieving smooth movement with minimal friction. The simplicity of this mechanical structure is also one of the secrets of Tamron's compact lens sizes.
Focusing elements inside the optical design make for better handling
In many lenses, the front elements move back and forth to alter the focus distance. With an internal focusing (IF) mechanism, the focusing elements are inside the optical design. Because the front lens elements remain static, the lens’ actual length does not change. This provides several benefits both to the image and during photography:
- The barrel is not subject to stray light entering from external helicoids that can adversely affect image quality
- A non-rotating front filter thread makes it easier to use filters such as graduated filters and polarisers
- A flower-shaped lens hood will remain in the correct position to most effectively shield the lens from stray light
- Better balance and more predictable handling because the lens length does not change during focusing
- Generally, a much closer minimum focusing distance throughout the zoom range
- Improved optical performance by minimising loss of illumination at the corners of the image field (vignetting)
- Suppression of other aberrations that become more troublesome at different focusing positions.
Integrated focus cam optimises internal focusing
Tamron's Integrated Focus Cam is a precision mechanical component that optimises the co-ordinated movement of the Internal Focusing (IF) system with the Multiple Cam Zoom Mechanism. This ingenious mechanism ensures accurate and seamless positioning of all the internal elements within the lens and coordinates them with the external zoom and focus controls.
Ultrasonic Silent Drive
'Travelling waves' generate a fast, smooth AF movement
This extremely quiet motor is ideal for photography of events, weddings, theatre or musical performances, as well as crucial moments on the golf course – any situation where autofocus noise is obtrusive. Major improvements in autofocus response and tracking ability over standard DC motors make for instantaneous focusing and spontaneous shooting of rapidly moving subjects.
Tamron’s USD works with the high-frequency ultrasonic vibrations that are produced by a ring called a ‘stator’. Energy from the vibrations is used to rotate an attached metallic ring known as the ‘rotor’. Piezoelectric ceramic is a material that produces ultrasonic vibrations when voltage of a specific frequency is applied is arranged in a ring formation on the stator. This electrode configuration of piezoelectric ceramic causes two ultrasonic vibrations to occur in the stator. By effectively combining these two ultrasonic vibrations, it is possible to convert the energy from the vibrations that produce simple motion into energy known as ‘deflective travelling waves’, which move around the circumference of the ring. The friction between these deflective travelling waves created on the metallic surface of the stator and the surface of the rotor produces force, causing the rotor to rotate. Attached to the rotor is the focusing lens, which is given a fast, smooth autofocus movement.
Smaller, lighter, faster and highly accurate AF
An exclusive Tamron innovation, the Piezo Drive (PZD) is an advanced ultrasonic autofocus (AF) motor based on the latest piezoelectric technology – the standing
wave principle. High-frequency voltage turns a ceramic piezoelectric element with a swiveling motion, causing the metal tip at the rotor's contact point to rotate elliptically, thereby turning the rotor to focus the lens swiftly, silently, and with great precision.
Standing wave ultrasonic motors like the one used in Tamron's innovative PZD have a number of advantages. They're smaller and lighter and also provide faster and quieter operation than DC motors for improved AF performance. Compared with their predecessors, their actuator system allows far greater flexibility in lens design, reducing the overall size and weight of the lens.
Useful when carrying the lens/camera over the shoulder
Another original Tamron mechanical engineering concept is the zoom-lock mechanism, which prevents the weight of the lens barrel from extending the lens when carried on the camera pointing downward. This eliminates the danger of accidentally knocking the lens while walking around and enhances responsiveness in the field. Simply zoom the lens out to its widest focal length and use the sliding zoom-lock switch to lock the barrel in place.
Autofocus/Manual focus system
Switching quickly between autofocus (AF) and manual focus (MF) is a great asset, especially in sports and nature photography. Tamron's ingenious system switches between the two focus modes by simply sliding the focus ring back or forth. Tamron lenses provide smooth, precise manual focusing with wide, well-textured focusing rings.
Multiple-cam mechanism for smooth, stable zooming and precise focusing at all focal lengths
The manufacture of compact, high quality, high-power zoom lenses became a reality only when Tamron perfected a lens chassis that permitted stable, smooth extension of the lens barrel. The Multiple Cam Zoom Mechanism is an original Tamron design that incorporates several precision cams cut into a single cylindrical surface by high-tech automated machinery. This key component enables zoom lens barrels to be extended and retracted effortlessly, achieving compact dimensions at the wide-angle settings while holding precise extension at telephoto settings.
Engineering plastics technology
To ensure the highest levels of performance and durability without adding additional weight, Tamron high-power zoom lenses make extensive use of engineering plastic materials in many critical mechanical components of the lens. Tamron has developed advanced proprietary methods for manufacturing these advanced polycarbonate materials to a very high degree of precision, and exhaustive testing has confirmed their long-lasting properties and dimensional stability under the toughest conditions. Indeed, polycarbonate of this calibre is the material of choice whenever Tamron produces high-precision components that must withstand rigorous use.