Tamron 17-50mm F/2.8 SP AF XR Di II LD (Canon)
Lightweight. Fast. Super Performance
This 17-50mm is an extremely high-quality standard zoom with a high luminosity of 2.8 over the entire focal length range. It belongs to the Super performance ( SP) class of Tamron lenses distinguished by ultra high optical and mechanical quality. The high luminosity that this lens offers is ideal for low-light conditions and professional image composition. The result is images with smooth, even bokeh (background blur), where the subject is virtually released from the background. Apart from the unlimited possibilities that this lens has to offer, it is the quality of your images that stand in the focus.
The world´s shortest minimum focus distance of only 27 cm was achieved, by using 3 XR glass elements (Extra Refractive) in the front group coupled with a new mechanical design, whilst at the same time keeping the construction compact. The maximum magnification ratio of 1:4,5 and a weight of mere 430 g are also a worldwide top. Image defects are kept at an absolute minimum through the application of aspherical elements and LD (Low dispersion) glass as well as a special coating of internal glass surfaces (Internal Surface Coating). The result is high-quality extremely sharp and excellent images.
Please note that Di II lenses are made for the exclusive use on digital SLR cameras with image sensors smaller than 24mm x 16mm. Di II lenses cannot be used together with a full format or 35mm SLR camera, as their image sensors are not able to cover the entire area of full format resulting in dark corners of the (i.e. vignetting becomes noticeable).
Delivering leading-edge image quality
The optical design of this lens uses a high-performance XLD (Extra Low Dispersion) element, which is manufactured out of a special glass with an extremely low refractive index. The refractive index describes the ability of the lens to split a light beam into its spectral colours. The dispersive properties are even lower than standard LD lenses and are at a level similar to fluorite. The XLD lens in combination with the LD element delivers the highest contrast and brilliance. This effectively prevents the problem of chromatic aberration in telephoto photography and delivers a high level of sharpness even in the peripheral regions. The result is a lens that effectively compensates for axial chromatic aberration and magnification aberration throughout the entire zoom range and guarantees the highest resolution and brilliance for your pictures.
Tamron's Super Performance series delivers a range of lenses that meet the highest standards.
XR (Extra Refractive Index) Glass
A special glass with a particularly high refractive index for greater performance and a compact lens design.
Hybrid aspherical elements ensure unique image quality and compactness.
LD (Low Dispersion)
Lens element for greater image sharpness and the correction of chromatic aberration.
The extension length of the lens does not change during focussing and the close focussing distance is significantly reduced across the entire focusing range.
Zoom Lock (ZL) Mechanism
Protects against undesired extension of the lens barrel.