Tamron Launches Fast SP AF17-50mm f/2.8 lens
Features Vibration Compensation for Nikon DX-format DSLRS2. Compact size with a filter thread of Ø72mm, while delivering both a large F/2.8 diameter and VC
While the size of a lens tends to increase when it’s equipped with an image stabilizer unit, Tamron has kept this lens as compact as possible through improvements to optical, mechanical and VC designs, thus achieving a remarkably compact size with a filter thread of 72mm.
Since the new Tamron 17-50mm VC lens is a large diameter f/2.8 zoom, the optical image stabilization system is also relatively large compared with previous VC lenses. To achieve the same anti-shake effect as the renowned VC mechanism incorporated into Tamron’s high power zoom lenses— models B003 and A20— the engineers had to enhance the VC unit itself, the mechanism that controls the optical image stabilization system. This initially led to an increase in size compared with existing lenses. It was therefore necessary to reduce the size of the VC unit while at the same time increasing its torque of driving power. This could only be achieved by bringing to all of Tamron’s advanced engineering capabilities that had enabled is to produce high-power zoom lenses and light, compact, high-speed standard zooms. After a prolonged program of development entailing exhaustive research and tireless testing, Tamron’s engineers finally achieved their goal, a fast, compact zoom lens with a filter thread of 72mm incorporating both a large f/2.8 maximum aperture and an effective Vibration Compensation mechanism.
This stunning achievement entailed innovations in both manufacturing technology and production engineering, including improvements to the precision, weight, and strength of the lens’ components. The result: The Tamron SP AF17-50mm F/2.8 XR Di II VC, an extraordinarily complex lens to manufacture but a joy to use.
3. The optical system, optimized for the characteristics of digital cameras, uses special glass for multiple elements, to enhance optical quality while maintaining compactness
With its innovative use of XR (Extra Refractive Index) glass, Tamron has optimized the overall optical power distribution and reduced the size of the lens, while at the same time implementing advanced correction of optical aberrations. In addition, the optimized positioning of three compound aspheric elements has enabled further shortening and compression of the entire optical system while maintaining outstanding imaging performance. Two LD (low dispersion) lens elements are also employed to make effective corrections for axial chromatic aberrations and chromatic aberrations due to magnification, a major factor in enhancing optical quality in digital photography. The result: excellent image performance throughout the zoom range.
• Optimizing the angle of light rays striking the image sensor
To reduce the impact of changes in aberrations due to zooming, the optical design adopted for this lens was developed to literally guide the angles of rays of light entering from the center to the periphery of the lens. This ensures that the light rays fall within a set range on the image sensor, enhancing image quality.
• Reduced fall-off of peripheral brightness
The fall-off in peripheral brightness that limits resolution in wide-angle shooting is very well controlled, resulting in excellent image detail from the center to the outer edges and corners of the image field.
• Superior resolution
As an SP Di II class lens, this lens delivers top imaging performance in all key parameters--high resolution, high contrast, and excellent detail rendition.