Great lens.Review by Simon
In developing the new Tamron SP 17-50mm F/2.8 XR Di II VC zoom, the primary goal was to maintain this incredible compactness and ease-of-use while simultaneously enhancing its convenience and expanding its performance envelope. As a result of concerted efforts, the engineers were able to incorporate Tamron's proprietary state-of-the-art Vibration Compensation (VC) image stabilization mechanism into the new lens without materially increasing its size and weight. As a result of this success, the SP 17-50mm F/2.8 XR Di II VC makes sharp hand-held photography possible under a vastly expanded range of photographic situations.
Tamron's proprietary VC (Vibration Compensation) image stabilization mechanism
Equipping a fast standard zoom with the advanced VC mechanism enables extended hand-held shooting possibilities along with enhanced versatility. It allows the full range of photographic expression, all the way from maximizing the expressive background-blurring effects by shooting at the maximum aperture of f/2.8, to fixed focus photography at the smallest apertures using extended depth of field.
Compact size with a filter thread of 72mm, while delivering both a large F/2.8 diameter and
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.
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 (lowdispersion) 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
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.
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.
Uncompromising countermeasures to reduce ghosting and flare
The latest BBAR (Broad-Band Anti-Reflection) multi-layer coatings are used to reduce reflection from the lens, ensuring excellent performance in all photographic conditions. The coatings enhance light transmission in both the short wavelength and long wavelength ranges. In addition, internal surface coatings (coatings on cemented surfaces of lens elements) have been applied to all cemented surfaces, for sharpness, optimum color reproduction performance and excellent color balance.
Minimum focus distance of 11.4" (0.29m) across the zoom range, with macro capability of 1:4.8
Even with its VC image stabilization optical system this lens delivers a minimum focus distance of 11.4" over the entire zoom range, enabling stress-free close-up photography. The maximum magnification ratio at 50mm is 1:4.8.
Simple, beautiful exterior design
A simple, classic design with a smooth silhouette has been adopted to ensure that this lens combines well with various SLR cameras. The highest quality textured paint has been used to give a superb finish to the exterior.
Zoom lock mechanism
Useful when carrying the lens/camera over your shoulder The lens includes Tamron's zoom lock mechanism to prevent the lens barrel from extending by its own weight when lens is being carried on the camera pointing downward.