The apex of telephoto lenses in a compact package, "SP 70-200mm F/2.8 DI USD delivers leading-edge image quality in a body that is the smallest in its class. Equipped with Tamron"s proprietary USD (Ultrasonic Silent Drive) motor, this lens boasts a speedy autofocus so you can capture that one decisive moment. One special XLD (Extra Low Dispersion) glass in concert with four LD (Low Dispersion) elements minimize chromatic aberrations. This combined with a new optical design that delivers high contrast and high resolution throughout the zoom range achieves leading-edge image quality. Tamron"s advanced multi-layer coating technology dramatically improves lens performance by reducing flare and ghosting for crisper, clearer images. The rounded diaphragm affords the photographer spectacular blur effects, delivering the kind of rich expression only achievable with a high-speed telephoto zoom lens. The most compact full-size, high-speed telephoto zoom lens features USD (Ultrasonic Silent Drive) to power a speedy AF drive together with a continuous manual focus mechanism. Moisture-resistant construction helps prevent moisture from penetrating the lens. Specifications: Model: A009: Focal length: 70-200mm: Maximum aperture: F/2.8: Angle of view (diagonal): 34°21′- 12°21′ (with full-size SLR cameras): 22°33′- 7°59′ (with APS-C sized sensor digital SLR cameras): Lens construction: 23 elements in 17 groups: Minimum focus distance: 51.2 in (1.3m): Maximum magnification ratio: 1: 8 (at f=200mm: MFD 51.2"): Filter size: Ø77mm: Length : 7.4 in (188.3mm): Entire length : 7.7 in (196.7mm)