Movie Makers (Jan-Dec 1950)

16 USING THE WIDE ANGLE LENS JAMES W. MOORE, ACL Photographs by LEO J. HEFFERNAN, FACL HAVE wide angle lenses got you wondering? Have you asked yourself what they are? What they do? Or even why they are called "wide angle" in the first place? If so, you have been asking sound and stimulating questions. The answers to them, we believe, can be of equal interest. Let's take a look. WHAT WIDE ANGLE LENSES ARE Putting it as simply as possible, a wide angle lens may be defined as a lens having a wider angle of view than that of the lens which is standard for the camera INCREASED AREA FIG. 1: Cramped and crowded is this Sunday morning scene, pictured with standard lens from farthest possible camera position. FIG. 1-A: Clear and composed is same scene shot with wide angle lens from same spot. Note increased coverage in both directions. involved. If this sounds at first like saying only that "a wide angle lens is a lens with a wide angle," let's look further into this definition. Let's look at the word "standard." WIDE COMPARED TO STANDARD When you bought your camera, it had mounted in it (normally) a single lens of a certain focal length. What the speed of that lens was is not important to our present discussion. But what its focal length was is of vital importance. With an 8mm. camera, this focal length would be % inch (12.5mm.) ; with a 16mm. camera it would be 1 inch (25mm.) in length. And with each camera this lens would be known as the normal or "standard" lens for the camera concerned. DEFINING STANDARD But why standard? And why a % inch lens in one case and a 1 inch lens in the other? Again simplifying, a lens is regarded as standard for a given camera when its focal length produces an image on the film which most nearly resembles in perspective the scene being imaged. And, to answer the directly related second question : the ideal or standard focal length of a lens varies depending on the size of the image it must produce. Thus it is that with the 8mm. camera and its frame size, the ^2 inch lens is regarded as standard. With the larger frame size of the 16mm. camera, the 1 inch lens is required to produce an image similar in coverage and perspective. Their angles of view, however, remain the same — approximately 20 degrees by 15, on the horizontal and vertical. SHORTER LENGTH-WIDER ANGLE What happens now, if we use on either of these cameras a lens of shorter focal length than the standard? Practically (with the screened image, that is), a number of interesting things happen — which we shall consider carefully in a moment. Technically what happens is that the shorter lens also takes on a wider angle of view; it becomes for the camera in question a wide angle lens. There have been established, however, certain focal lengths which are regarded as being the wide angle lens for each size of camera. J/or 16mm. cameras this lens is almost universally 15mm. in length (as opposed to the 1 inch, or 25mm., standard) ; with an 8mm. camera the wide angle lens varies from 7 to 7.5 up to 9mm. in focal length. There also are available for each camera accessory wide angle lenses. These, when fitted over the standard lens of the camera, shorten its focal length (but do not change its speed) to create the same effects as a prime wide angle objective. LARGER FIELD FIRST EFFECT Certainly the best known effect of the wide angle lens is its ability to enlarge the camera's field of view from a fixed camera 'position. For the family firmer this often may mean the difference between getting a desired scene and not getting it. With his back literally against the wall, he simply shifts from his standard lens to the wide angle for the needed coverage. [Continued on page 34]