Thuật ngữ - ký hiệu ống kính Tamron TAMRON LENS GLOSSARY - TERMINOLOGY - ABBREVIATIONS Ống kính Tamron AD (Anomalous Dispersion) - Chất liệu kính cho phép kiểm soát tốt hơn hiện tượng sắc sai, giảm hiện tượng sắc sai và cho hình ảnh chất lượng hơn. ASL (Aspherial) - Thấu kính (gần như) phẳng, có tác dụng chống cầu sai, làm tăng độ chính xác của hình ảnh và tạo khả năng sản xuất các ống zoom tỷ lệ lớn hơn. BIM (Built-in Motor) - Mô-tơ gắn trong ống kính dành riêng cho thân máy Nikon. Di (Digitally Integrated Design) - Thiết kế tích hợp công nghệ số nhằm sản xuất các thấu kính / ống kính phù hợp với máy ảnh số. Các thân máy cảm bién cúp nhỏ (APS-C) cũng có thể sử dụng ống Di nhưng sẽ có một số hiệu ứng khác với khi lắp trên máy toàn khổ như hiện tượng tối mép ảnh giảm, boke giảm, v.v… Di II (Digitally Integrated Design II) - Thiết kế tích hợp công nghệ số 2. Các ống Di II phù hợp với máy ảnh số DSLR có cảm biến cúp nhỏ APS-C. IF (Internal Focus) - Hệ thống căn nét trong với các thấu kính chuyển động bên trong thân ống. LD (Low Dispersion) - Chất liệu kính cao cấp làm thấu kính có độ tán xạ thấp, giảm thiểu hiện tượng tán xạ làm tăng chất lượng hình ảnh. SP (Super Performance Series) - Dòng ống kính có hiệu năng siêu việt, chất lượng cao, cho hình ảnh đẹp. USD (Ultrasonic Silent Drive) - Cơ chế căn nét tự động gắn mô-tơ siêu êm không phát ra tiếng động và căn nét chính xác. VC (Vibration Compensation) - Thuật ngữ Tamron sử dụng chỉ các ống kính có gắn hệ thống chống rung, làm giảm tác động của hiện tượng rung tay máy. XLD (Extra Low Dispersion) - Chất liệu kính cao cấp làm thấu kính có độ tán xạ siêu thấp, tăng cường chất lượng hình ảnh. XR (Extra Refractive Index) - Thủy tinh chiết xuất cao, có khả năng “bẻ” các tia sáng ở góc hẹp hơn giúp sản xuất ống kính có chiều dài ngắn hơn đồng thời giảm cầu sai. ZL (Zoom Lock) - Ống kính có lẫy khóa chống tụt ống zoom khi mang đi mang lại. Đặc biệt cần thiết khi ống đã sử dụng nhiều. VinaCamera.com 2008-2010 ENGLISH Di - Digitally Integrated Design Di is a Tamron designation that applies to lenses that have been optimised for digital capture using advanced multi-coating techniques and optical designs that assure excellent image quality across the entire picture field. Because of these characteristics, Di lenses provide outstanding performance on cameras with full- frame and APS-C format sensors as well as on 35mm film. Di II - Digitally Integrated Design for DSLRs with small sensors Di II lenses are designed for exclusive use on digital SLR cameras with APS-C-format image sensors. All Di II lenses are optimised to meet the performance characteristics of DSLRs, providing maximal resolution concentrated within the image field and assuring that light rays at the edges of the frame reach the sensor at favourable angles, thereby minimising peripheral light falloff. In addition, all Di II lenses incorporate effective measures to increase light transmission and eliminate ghosting and flare, which are particularly noticeable with digital cameras. Tamron’s advanced multi-coatings are applied not only to external and internal lens surfaces, but also to surfaces in between cemented lens elements. Finally, Di II lenses are offered in a wide array that includes the focal length ranges most desired by DSLR shooters. XR - Extra Refractive Index 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. This has allowed Tamron to develop a line of shorter, smaller-diameter, lighter lenses without sacrificing lens speed, actually upgrading image quality compared to older designs. XR glass is costlier than conventional glass but it yields enhanced optical power distribution, making possible many of the outstanding and innovative lens designs that bear the XR designation. SP - Super Performance series Tamron SP (Super Performance) series is a line of ultra-high-performance lenses designed and manufactured to the exacting specifications demanded by professionals and others who require the highest possible image quality. In creating SP lenses Tamron’s optical designers put their foremost priority on achieving superior performance parameters – they are all designed to a higher standard with little regard for cost constraints. As a result, Tamron lenses bearing the SP designation feature impressive and innovative designs that have established an enviable reputation for excellence among those knowledgeable photographers that demand the very best. ASL - Aspherical Tamron uses several hybrid aspherical lens elements in its lenses bearing the Aspherical designation. These innovative optics achieve the ultimate in image quality while producing lenses that offer remarkable zoom ranges in extraordinarily compact packages. These cutting-edge advances have advanced the state of optical design by virtually eliminating spherical aberration and image distortion from Tamron’s high-power-zoom series. As one hybrid aspherical lens element can take the place of multiple elements without compromising performance, remarkably compact long-range lenses can now deliver a uniformly high level of image quality across all focal lengths and apertures. LD - Low Dispersion 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. XLD - Extra Low Dispersion XLD lens elements are made from a sophisticated 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. The dispersive properties of the XLD lens are similar to those of fluorite; in combination with the LD elements, these make for an optimal optical design that delivers best-in-class resolution with advanced correction of axial chromatic and magnification aberrations – major inhibitors of image quality enhancement. The result is a lens that delivers sharp contrast and better descriptive performance throughout the entire zoom range. AD - Anomalous Dispersion 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. HID - High Index High Dispersion 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. VC - Vibration Compensation Tamron’s unique VC mechanism uses a proprietary actuator and algorithms to deliver an extremely stable viewfinder image with excellent tracking. The mechanism employs three driving coils which activate the shake-compensating VC lens group electromagnetically via three steel balls. The VC lens elements are held in place only by contact with the steel balls, achieving smooth movement with minimal friction. The simplicity of this mechanical structure is also one of the secrets of Tamron’s compact lens sizes. IF - Internal Focusing Tamron’s internal focusing (IF) mechanism provides numerous practical benefits to photographers including: - a non-rotating front filter ring that facilitates the positioning of polarising and graduated filters - more predictable handling because the lens length does not change during focusing - a much closer minimum focusing distance (MFD) 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. USD - Ultrasonic Silent DriveUltrasonic Silent Drive 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. BBAR coating – Broad-Band Anti-Reflection 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. Zoom Lock Another original Tamron mechanical engineering concept is the Zoom Lock, a simple convenience feature that prevents undesired extension (creep) of [...]... great asset in many types of shooting, especially sports and nature photography This is easily accomplished with Tamron s ingenious AF/MF system By simply sliding the focus ring back and forth between the two positions you can select either the AF or the MF focusing position In manual focus mode Tamron lenses provide smooth, precise manual focusing by turning their wide, welltextured focusing rings Specifications, . Thuật ngữ - ký hiệu ống kính Tamron TAMRON LENS GLOSSARY - TERMINOLOGY - ABBREVIATIONS Ống kính Tamron AD (Anomalous Dispersion) - Chất liệu kính. Compensation) - Thuật ngữ Tamron sử dụng chỉ các ống kính có gắn hệ thống chống rung, làm giảm tác động của hiện tượng rung tay máy. XLD (Extra Low Dispersion) - Chất