Nikon D200 D200 User's Manual - Page 186

CPU lenses can be identified by the presence of CPU contacts. Type G lenses are marked with a "G" on the lens barrel, type D lenses with a "D." CPU lens Type G lens Type D lens Type G lenses are not equipped with a lens aperture ring. Unlike other CPU lenses, there is no need to lock the aperture ring at the minimum aperture setting (maximum f/-number) when using a type G lens. Picture Angle and Focal Length The diagonal picture angle of the D200 is less than that of a 35-mm camera. When calculating the focal length of the lenses for the D200 in 35-mm format, multiply the focal length of the lens by about 1.5: Option 35-mm camera D200 35-mm camera D200 Approximate focal length (mm) in 35-mm format (modified for picture angle) 17 20 24 28 35 50 60 85 25.5 30 36 42 52.5 75 90 127.5 105 135 180 200 300 400 500 600 157.5 202.5 270 300 450 600 750 900 Technical Notes-Optional Accessories 176 Calculating Picture Angle The size of the area exposed by a 35-mm camera is 36 × 24 mm. The size of the area exposed by the D200, in contrast, Lens is 23.6 ×15.8 mm, meaning that the diagonal picture angle of a 35-mm camera is approximately 1.5 times that of the D200. Picture size (35-mm format) (36 mm × 24 mm) Picture diagonal Picture angle (35-mm format) Picture angle (D200) Picture size (D200) (23.6 mm × 15.8 mm)