The Tamron AF 18-250mm f/3.5-6.3 Di-II LD Aspherical IF Macro Lens utilizes a custom-built optical system specifically engineered for digital SLR cameras. This design effectively corrects aberrations, such as astigmatism, while achieving a compact form factor through the downsizing of the initial group. The outcome is a lens that delivers exceptional zoom capabilities and superior optical quality.

In the initial lens group, the inclusion of one LD (Low Dispersion) glass element and one AD (Anomalous Dispersion) lens effectively reduces on-axis chromatic aberration. Additionally, the integration of two hybrid aspherical lens elements within this group ensures compactness is maintained despite the lens's substantial 13.9X zoom power.

The lens incorporates Internal Surface Coatings, which consist of multiple-layer coatings applied to the cemented surfaces of several elements, along with advanced multiple-layer coating technology on standard elements. These enhancements are aimed at minimizing reflections caused by light entering through the front element and mitigating image degradation effects caused by the imagers themselves.

The Zoom Lock prevents unwanted barrel movement when carrying the lens/camera combination. 

The design has been enhanced with the addition of a gold-colored band positioned between the focus and zoom rings, elevating its aesthetic appeal and distinguishing it as a Di-II lens. Simultaneously, the rubber patterns on the zoom and focus control rings have been refined to harmonize with modern digital camera aesthetics and improve overall handling.