User manual NIKON FISHEYE-NIKKOR 6MM F/2.8

[. . . ] 8 applies the equidistant projection formula (y = Cd) in order to accommodate the extra-wide picture angle within a field of finite size. The zenith angle of any point in the image recorded on film is proportional to its distance from the center of the image (see Photogrammetry, page 14). This makes the lens suitable for scientific requirements such as measuring the zenith or azimuth angles of astronomical bodies or recording cloud distribution patterns in the sky. [. . . ] the automatic diaphragm feature and wide f/2. 8 maximum aperture guarantee the brightest possible image for viewing and focusing, even in dim light. Depth of field can be observed by simply pressing the camera's depth-of-field preview button; or, refer to the table on page 34. Il Recommended Focusing Screens Various interchangeable focusing screens are available for F2 and F3 Nikon cameras to suit any type of lens or picture-taking situation. Those which are recommended for use with the Fisheye-Nikkor 6mm f/2. ^ " - - - ^ ^ ^ Screen Camera ^ " " " " - - - - ^ ^ A/L B C D E G1 G2 G3 G4 HI H2 H3 H4 J K/P M R A A T F3 F2 © © ® © © © © © © © ® -a © © © © © © © © © © © © • When the Teleconverter TC-200 is attached to this lens, use the following table: ^ " ~ ~ ~ - \ ^ ^ Screen Camera -^^ A/L B F3 F2 • © ® © -Vz O * Excellent focusing ®= Acceptable focusing The image is brilliant from edge to edge, but the central rangefinder, microprism or cross-hair area is dim. But the image on film shows no traces of this. A= Acceptable focusing The in-focus image in the central spot may prove to be slightly out of focus on film. Q= Exposure measurement not possible; lens/screen combination permits only focusing operation. , — y2) in the tables above mean that the film speed (ASA/ISO) should be set against the proper compensating mark as shown in the diagram below. When no exposure correction is indicated, the film speed (ASA/ISO) in use should be opposite the • index. C D o o o o E G1 G2 G3 G4 HI H2 H3 H4 J K/P M R T © © O O © ® © ® ® o o COMPOSITION Using a fisheye lens requires much more thought and planning about picture composition than does a conventional lens. The lens not only produces wideangle distortion but also exaggerates the relative size of objects to conform to its circular format. Objects near the center appear larger than those at the edges, and they show less optical distortion. The entire field is pushed into the distance and spatial relations are transformed. and a slight shift in camera position produces a whole new set of distortions. [. . . ] The center of the image corresponds to the zenith in the angle of view, and the distance of any point in the image from this center is directly proportional to its angle from the zenith, expressed by the equation y = CO, where y is the distance of the point from the image center, 6 is the zenith angle, and C is a constant (see below). For example, a point j n the image 4mm from the center represents an object at an angle of 37. The table below gives zenith angles for points at given distances from the center of the film image. [. . . ]