Tamron lenses are quite popular among professional as well as amateur photographers. Designed in all-black polycarbonate body, the SP AF 200-500mm f/5-6.3 Di LD (IF) of Tamron is intended to satisfy the performance characteristics of digital SLR cameras and will also work well with 35mm SLR cameras. This zoom lens is constructed of 13 elements in 10 groups.the lens uses two LD(Low Dispersion) glass elements to compensate for on-axis and lateral chromatic deviations, a critical aspect to improve the optical excellence in digital photography. The lens has a close focus distance of 98.4â€(2.5m) at all focal lengths. Maximum magnification is 1:5 (at 500mm). The zoom ring rotates around 95 degrees throughout the full range. A Zoom Lock prevents unwanted barrel extension when carrying the lens-camera combination. A M/AF switch is provided for switching between manual and auto focus. The Filter Effect Control is designed to rotate the filter to the preferred position with the hood attached, facilitating you to simultaneously perform minute adjustments to the polarizing filter compensation. The polarizing effect can be confirmed through the viewfinder, at the same time maintaining the hood on to avoid the harsh light. Other specifications include the diaphragm blade number which is 9 and weight of the lens which is 1237g(43.6oz).