The major components of a camera are its lens, shutter and the aperture which controls the intensity of light flowing through the lens, as the shutter opens and closes. The shutter operates a great deal like a window shade to control the amount of time the film is exposed to light. To a considerable extent this influences the capture of motion or movement on film. The longer the shutter is open, the more movement that is captured. Another type of shutter has overlapping blades which open together to expose the entire scene at once. This will be discussed in further detail under "Camera Operation."

The most popular and prolific camera now in use is the 35 millimeter (mm) single lens reflex device. So, that is the one we'll talk about here. But one must also understand the role film plays and the importance of selecting the right film for the environment, scene or subject being photographed. In addition, understanding framing or composing factors for the photograph, its elements and their dimensions, is equally important. Though similarities between an eye and a camera lens are apparent, the photographer must understand and be alert to their differences!

Foreground, background, distances, angles, light variations and other factors will significantly affect the success of the photographer in capturing a scene or subject in a photograph, as intended. This series provides some valuable insights and pointers to help in your next picture-taking excursion. In this issue we'll explore camera operation and in later issues delve into light management, selection and care of film, composition of photographs, film processing and printing your pictures in future issues.

The 35mm single lens reflex (SLR) camera is the one most widely used and the focus of this discussion. The term, 35mm, refers to the width of the film. Single lens reflex means that what you see through the viewer is what you get on the film. You are looking through the actual lens. There is a movable mirror behind the lens, and a ground glass or other screen for viewing the image. Just prior to the shutter opening, the mirror moves out of the way to permit the image to fall over the film. A ground glass of granular textured surface is used as a focusing panel. There are two types of focusing prisms, split image or split field where the view image is divided into two parts by a fine line and the superimposed field, where two images of a scene are brought into coincidence for focus.

Another type of 35mm camera is known as a viewfinder or range finder. The principal difference of that camera and a SLR camera is that, though the viewer and camera lens are lined up, the photographer sights through the viewer and not through the photographing camera lens. Thus, the photographer does not really see exactly what the camera is photographing. The advantage is that the viewfinder cameras have a quieter operation and the viewer is brighter. Besides not enabling the photographer to see what is being photographed, another disadvantage is the photograph may be distorted by an obstruction (such as a finger or strand of hair) in front of the lens or a dirty lens. Another disadvantage is the need for a separate lens for the viewfinder that must be changed when changing the lens used to produce the photograph.

With such a variety of 35mm cameras on the market, the features of a particular camera must be carefully considered. For example, for professional photographers, manual capabilities are a must, whereby "high-end" automatic cameras can provide the service required by most "non-professional" photographers. When the auto-focus 35mm SLR cameras first emerged, they were less impressive in their performance than those now on the market. Focusing earlier versions took too long as well as restricting where to focus. However, current automatic camera products are more consistent in capabilities with the eye. But professional photographers still require a camera with manual, single object and continuous focusing capabilities, often provided with the newer automatic cameras.

One of several common components of a manual 35mm camera is the shutter.

The shutter controls the amount of time films are exposed to light. The shutter controls motion or movement shown on the film. The longer the shutter stays open, the more movement is captured on the film. The faster the shutter opens, by setting it at a higher number, the more the action is stopped.

Two types of shutters are focal plane and leaf shutters. The focal plane operates like a window shade; one opens as the other closes. The leaf shutter operates with a set of overlapping blades and is mounted between the lens elements. When the shutter is released the blades open outward from the center exposing the entire frame at once. The focal plane is more common and the advantage is the photograph can be shot with higher speeds then with the leaf. However the leaf has more capabilities with flash, the draw back being the cost of the individual lens. Faster shutter speeds prevent any depiction of movement (or action). For slower shutter speeds a tripod is needed to prevent movement of the camera which would distort depiction of movement by the subject. Also, a time-exposure shutter-control may be needed.

Most shutter controls have settings of number 4, 2, 1 color-coded then 2,4, and 8, 15, 30, 60, 125, 250, 500, 1000 in white. One number, either 60,125, or 250 is in red, which designates the highest shutter speed useable (in synch) with a flash. The color code numbers stand for the time the shutter is open in seconds. The white numbers stand for the amount of time the shutter is open in fractions of a second such as 60 is one sixtieth of a second, 2 is one half a second etc.

Most shutter speed controls have the letter B that stands for time exposures. The camera should be set on a tripod for photographs shot below 60th of a second, as motion could be detected from movement related to the photographer’s balance. However, to show action within still photographs, a technique called panning can be used. This technique requires a very slow shutter speed below a 15th of a second and that the photographer move with the object being photographed, which is also moving. However, if your subject is still, as in this flowing brook picture, you can control the noticeable motion of the stream in your photograph. A slower shutter speed was used to produce the image on the right, which exhibits a more distinct blurring of the water flow than the image on the left.

The iris diaphragm is a set of overlapping blades inside a lens. The hole in the diaphragm is called the aperture. This component has the same function as an iris in the eye, managing sight according to light intensity present. For the camera, the aperture controls light intensity to which the film is exposed. The sizes of the aperture are referred to as "f" stops.

Every lens has an iris diaphragm and the quality of a lens is determined by the range of f-stops. The numbers indicate the size of the opening running backwards to common sense. The smallest opening is f22 with the largest opening being f2.8. An f2.8 lens is much sharper than as f4 lens. Common terms referring to aperture controls are "stop down," meaning to set the aperture at a smaller opening or larger f stop, and "open up," meaning to set the aperture to a larger opening or smaller f stop.

A wide variety of lenses are available for 35mm cameras. The numbering system for lenses also use "f" in their sizing. In the 50mm or f50 lens, "f" stands for focal length, not "f stop." The focal length of a lens is the distance from the optical center of the lens to the film plane. A short focal length lens is considered a wide angle lens and is smaller then a 50 mm lens. A long focal length lens is referred to a telephoto lens and is higher than a 50mm lens.

A "fixed focal length" lens is considered a "non-zoom" lens. The normal focal length is consider a 50mm lens and there is no distortion in the image, very little space/shape distortion, as exhibited by the photograph below. A wider angle lens, 35mm and lower, has a wide field of view causing subjects to appear smaller and farther away.

Generally, zoom lenses are popular with most photographers, but not with professionals, due to their limited maximum aperture (f4 common in zoom lenses). Depth of field is clearly exhibited in this photograph reporting a bicycle race.

The distance that remains in focus in the focal plane of the scene determines the "depth of field" of the photograph. This is the distance between the closest and most distant objects in focus. Both the lens and aperture affect the depth of field. The smaller the aperture (f16) the greater the depth and the larger the aperture (f4) the less the depth of field, though focusing is critical.

Automatic cameras make many camera component settings, but the photographer must ensure that some are properly set. The "M" manual setting matches up either the light dial or tab metering system, while the "A" aperture priority setting sets the aperture such that it will not be changed by the camera, causing only adjustment to the shutter speed (useful for control of depth of field), while the "S" setting gives shutter speed priority and won't allow it to change but enables changes to the aperture (useful for control of motion).

"P" is the program mode setting which enables the camera to maintain moderate shutter and aperture settings to optimize exposure according the the light environment. In our next issue, we will explore this environment and the challenges involved in managing light to make pretty pictures.