TOMMY WILLIAMS / L’Observateur / July 31, 1999

Sometimes you have to dig a little deeper to have a better understanding of the different camera mechanisms that are essential for proper operation of your camera in manual mode, mainly the lens aperture, camera shutter and the meter system. This article contains both old and new information.The aperture is located in the lens and operates similarly to the iris of your eye.

The diameter opening of the aperture will determine both the amounts of light that will reach the film and your depth of field (how much will be in focus).

While operating in manual, if the current setting is 125 shutter speed with an aperture (or f-stop) of f-8, and you close down the f-stop to f-11, you’ll have to slow down the shutter speed to 60/s. For every increase in f-stop, such as f-8to f-11, the amount of light passing through the lens is reduced by half. On theother hand, as you decrease the f-stop from f-11 to f-8, the amount of light doubles, you would then have to increase the shutter speed back to 125/s.

The camera’s shutter on the other hand, also controls the amount of light reaching the film due to the duration or amount of time it remains open, similar to a door opening and closing. As the shutter speed increases or decreases, theamount of light that reaches the film will increase or decrease correspondingly.

As you reduce the shutter speed, you increase the aperture setting to compensate for more light, and as you increase the shutter speed, you’ll have to decrease the aperture. The shutter speed also will determine the amount ofcamera blur or motion that will appear in the photo. As the shutter speedincreases, the subject motion decreases, and as the shutter speed decreases, the subject motion increases.

Lastly, your camera will be equipped with some type of photo cell or metering system in which helps you to determine the proper aperture and shutter speed combinations to produce adequate film exposure. A camera’s metering system,regardless of its type, reads the reflective light. Reflective light is the amountof light reflected off or from the subject toward the camera. White walls, sky,beach sand and snow are all different types of scenes that can create cause improper or underexposed negatives due to the large amounts of light they reflect. Dark backgrounds, on the hand, such as night scenes and dark walls cancause overexposure to your negatives. The meter sort of acts like a balancingscale, if you choose f-8 for your aperture setting, the meter will indicate which corresponding shutter speed will be necessary for a proper exposer. Or, if youwant to use a specific shutter speed, the meter will indicate the proper aperture setting.

All three, aperture, shutter and light meter, work together to produce proper film exposure.

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