The Tameron 28-200mm,
zoom lens has plenty of the latest technology attributes, and may be used with over 200 different
35mm cameras, both new and old. In addition, Tamron has launched an updated cosmetic appearance with the announcement of this 28-200mm lens, revising the focus and zoom ring patterns for improvement ease of overall handling.
It has a zoom ratio of 7.1X which covers focal lengths ranging from wide to extended telephoto on both APS-C DSLRs and full-frame cameras, a perfect lens for travel photography,, sports action, and creative expression. It provides exceptional image quality over the entire range, as close as 19.3 inches (1:4 at 200mm) while weighing only 12.5oz.
This compact, lightweight, high power zoom features a Di optical system containing an improved multi-coating designed for DSLR cameras plus
full frame size digital cameras, additionally enhancing its popularity and ease of use.
Nov 19, 2011
Aspherical Lens - a lens whose curved surface does not conform to the shape of a sphere. An aspheric element is often
called an aspherical lens. The asphere's more complex surface profile can eliminate
spherical aberration and reduce other
optical aberrations compared to a simple lens. A single
aspheric lens can often replace a much more complex multi-lens system. The resulting device is smaller and lighter, and possibly cheaper than the multi-lens design. Aspheric elements are used in the design of multi-element wide-angle and fast
normal lenses to reduce aberrations.
DI - Digitally Integrated Design (to reduce
ghosting, flare, CA and peripheral light fall-off along with improved resolution)
Internal Focusing Internal focusing
lens (also known as IF) is a
photographic lens design in which focus is shifted by moving the inner lens group or groups only, without any rotation or shifting of the front lens element. This makes it easy to use, for example, a screwed-in
polarizing filter or a petal shaped lens hood. During
macro photography, using an internal focus lens reduces the risk of the front of the lens accidentally hitting the subject during focusing as the front element does not move.
The first most important reason that the lens is so compact is the use of high refractive index glass. That is, XR glass. High refractive index glass bends light more than normal or lower refractive index glasses. Normally, glass material having a refractive index of more than 1.69 is called high refractive index glass. In the A03 optical system, glass material having a refractive index of more than 1.69 is used in the front group. In addition, refractive index of the whole optical system is enhanced. By using high refractive index glass in the front group, we could make the elements in the first group thinner, and reduce one element in the second group. This made the overall length of the whole optical system shorter.
Shop for the Tamron AF 28-200mm F/3.8-5.6 XR Di IF Lens here from these stores