The Sony SAL500F40G 500mm Lens is a very long telephoto lens with a very fast f/4.0 aperture that puts you right into the action for sports or nature photography. It features three ED (Extra-low Dispersion) glass elements and Nano AR lens coatings that fight flare, maintain excellent contrast and reduce internal reflections. When you're shooting sports or nature subjects, you're always fighting the elements and this lens does its part--it has interlocking weather-resistant seals in and around the focusing ring and other vulnerable points to protect against moisture, dust and grit.
The 500mm f/4.0 is compatible with the Sony SteadyShot in-camera image stabilization system and it has a Super Sonic Wave Motor (SSM) with a drive circuit four times as fast as previous versions. The autofocus is fast and quiet. When used with a compatible APS-C format DSLR, the equivalent focal length of this lens is a whopping 750mm.