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, in SP lenses of fixed focal length, molded glass aspherical elements deliver planarity in field curvature. These elements ensure superb focusing uniformity over the entire field by compensating for spherical and comatic aberrations. 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.
LD – Low Dispersion
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.
XLD – Extra 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.
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
BBAR – Broad-Band Anti-Reflective coating
Cleaner, crisper images without flare or ghosting
BBAR coating provides crystal-clear images by suppressing element surface reflections that lead to ghosting and flare.
Developed for industrial optics, fluorine coating offers long-lasting oil and water resistance to the lens. Moisture and smudges wipe away, making it easy to keep your lens clean.
Optimal relative illumination
The two new SP lenses deliver exceptionally uniform illumination levels across the image field to avoid non-linear pattern or fall-off toward corners.
9 diaphragm blades for superb blur quality
The number of diaphragm blades affects the “shape” of the blur in out-of-focus areas of the image. This is more important in portraiture, where the aperture setting is often wide open, and macro photography, where the high magnification results in blurred background and foreground even at narrow apertures. When backgrounds are soft and blurred, not only is the effect very pleasing and “photographic”, but it also serves to isolate the subject from a distracting background, providing a professional-looking image. A high number of blades provides a rounder shape to the aperture, which in turn makes the shape of the blur more circular and much more natural.