Nikon's AF-S fast fifty — the 50mm f/1.4G with silent wave motor.
The Nikon AF-S Nikkor 50mm f/1.4G, released in 2008, replaced the older AF Nikkor 50mm f/1.4D with a new optical formula featuring Internal Silent Wave Motor (SWM) autofocus, a modified rear floating element for improved close-focus performance, and a G-type construction without an aperture ring.
50mm focal length, f/1.4 maximum aperture, nine-element seven-group optical formula with aspherical element, SWM silent autofocus, Nikon F mount, G-type (no aperture ring), 58mm filter thread.
The AF-S 50mm f/1.4G provides fast, silent autofocus and good wide-open performance; at f/1.4 some field curvature and coma are present but improve markedly by f/2. By f/2.8 field uniformity is excellent. The G designation (no aperture ring) means aperture cannot be controlled on older Nikon bodies without a CPU connection.
Test AF accuracy at near (1m) and far distances — focus shift with stopping down is sometimes reported. Inspect elements for fungus or haze. Confirm SWM AF drive is smooth and quiet. Check mount contacts. Verify the camera body supports G-type lenses if using an older Nikon body.