User manual NIKON FISHEYE-NIKKOR 8MM F/2.8

[. . . ] 8 means that the viewfinder image is extra-bright for easy viewing and focusing even in dim light. Barrel distortion is considerable, since the circumference of the image circle corresponds to a straight line. The equidistant projection formula (y=C0) is used in order to accommodate this extra-wide picture angle within a field of finite size. [. . . ] 11 COMPOSING Composing with a fisheye lens requires much more thought and planning than with a conventional lens. The lens not only produces wideangle distortion but it also exaggerates the relative size of objects to conform to its circular format. 8 offers the photographer the maximum possible control over picture composition with reflex viewing and focusing control. Be careful not to include in the picture unwanted objects such as the legs of a tripod or the photographer's hands or feet. Also, try not to let too much direct sunlight strike the lens as this may cause ghost images. One way to prevent this is to create an artificial "eclipse" using a three-inch diameter shield attached to a thin rod or wire. Hold the shield in front of the lens in such a way that it blocks out the direct rays of the sun. The further you hold the shield from the lens, the less conspicuous it will be in the final photograph. USING B U I L T - I N F I L T E R S D A set of five filters is built into the rear end of the lens mount: skylight (L1BC), medium yellow (Y48), deep yellow (Y52), orange (056) and red (R60). These filters are mounted on a revolving turret so they can be moved into place quickly one after another. Turn the knurled filter selector dial on the side of the lens mount until the desired filter designation on the rim of the dial clicks into place. The skylight filter (L1BC) is used in either black-and-white or color photography. The others are normally used to subdue the effect of certain colors or to increase image contrast in black-and-white photography. The table below shows the filter factors for film rated at ASA/ISO 100. [. . . ] €¢ = Exposure measurement not possible Lens/screen combination permits only focusing operation. 8 ~ f/22 on both standard and aperture-direct-readout scales Exposure measurement: Via full-aperture method; meter coupling ridge provided for Al cameras and meter coupling shoe for non-AI cameras Distance scale: Graduated in both feet and meters from 0. Le centre de l'image correspond au zenith dans Tangle de vue, et la distance de tout point de cette image au centre est proportionnelle a Tangle qu'il forme avec le zenith, ce qui s'exprime par Tequation y=C0, ou y represente la distance entre le point et le centre de l'image, 6 Tangle zenithal, et C une constante. [. . . ]