Paving the way for Tamron's all-in-one zoom lens, Model 71D lens was unveiled in 1992 featuring 28-200mm focal length and 7.1x optical zoom. The optical build incorporated Tamron's unique, creative and high performance technology. Aspherical elements were arranged to permit a decrease in the number of lenses and increase design flexibility, while ensuring more effective aberration corrections. The lens employs Tamron's Triple-Cam zoom system and an engineered plastic which protects the complex structure from shocks and helps reduce the weight of the product. The lens sports 16 elements in 14 groups, 6-blade diaphragm, 2ft 7.5" close focus distance and 72mm filter thread.