A:Answer The Nikon Nikkor 500mm F/4 D ED IF AF-I is an archived lens that offered a Nikon Silent Wave Motor, 9 elements in 7 groups and 9 diaghragm blades. It was significantly heavier than the Nikon AF-S NIKKOR 500mm f/4E FL ED VR lens. Since the Nikon Nikkor 500mm F/4 D ED IF AF-I's release there have been remarkable improvements in technology. The Nikon AF-S NIKKOR 500mm f/4E FL ED VR lens represents those improvements. This evolutionary lens has an Electromagnetic Diaphragm Mechanism in the barrel which provides highly accurate electronic diaphragm or aperture blade control when using auto exposure during continuous shooting. With conventional D/G type lenses, the diaphragm blades are operated by mechanical linkage levers. In addition, this lens model has a Fluorite lens element, which allows for excellent optical properties and reduces the overall lens weight to improve handling.
