XR (Extra Refractive Index) Lens Elements
UXR (Ultra Extra Refractive Index) Lens Elements

By minimizing the overall length of the optical system, Tamron has succeeded in drastically reducing lens diameter and reducing overall lens size for the same focal length and same maximum F-number. By utilizing XR lens element, Tamron has achieved a compact size together with good correction of aberrations while maintaining the optimum balance of overall optical power. Moreover, through the active utilization of UXR lens element, Tamron has developed even more compact designs while achieving good correction of aberrations.

Principles enabling more compact sizes at the same lens brightness

XR lens element, with its superior light-bending power, makes it possible to design a short-barrel lens with the same light-gathering ability (aperture value) as a long-barrel lens—even with a smaller lens diameter. By using this principle Tamron has been able to shorten the length of the entire optical system and produce lighter, more compact lenses of the same speed, and also to provide greater zoom ranges in lenses that are much more convenient to carry and hand-hold.