The 28-300 mm XR (Model A06) zoom achieves a remarkable 25% reduction in size, and 28% reduction in weight compared with the previous 28-300 mm (model 185D) - making the A06 the smallest, lightest 28-300 zoom in existence today. To achieve such compact, lightweight lens design, Tamron further improved upon the Moving Triple Cam technology introduced in the 28-200 XR (Model A03), achieving a solid, stable two-step extension action mechanism to attain the 300 mm zoom setting. XR (extra Refractive Index) glass is effective in reducing the optical length of the lens through high refractivity. LD (Low Dispersion) and AD (Anomalous Dispersion) glass minimize loss of sharpness caused by color blurring at the tele end of the focal range, while ensuring vivid, quality imaging. The ASL lens technology compensates for spherical aberration to achieve outstanding image quality. At the same time, reducing the number of elements results in a more compact, lightweight lens package.