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Correct exposure estimate

Some photographers follow the method of (estimation) to estimate exposure factors, trusting them in their (personal experience). Portraits, for example, have already known (through daily personal experience) the appropriate amount of exposure to photograph the face of a person who comes to him and sits in front of the camera, and uses sources of information of strength and distances from the customer »with an approximately specific distance, and usually uses a specific film of known and familiar sensitivity to him. And a fixed method used to show the film, etc.

Such a photographer, whose work is carried out in a certain routine, does not need to bother researching the factors that affect the estimation of the exposure factors, as it suffices him to do several experiments at first, after which he reaches the optimal result, and so on in this way. This applies to any other photographer who constantly uses certain light sources and fixed distances from objects of an almost close nature, etc. As for those who dictate their circumstances! Filming in different conditions, whether with regard to light sources or with regard to the types of sensitive films or the colors and shapes of the objects they wish to photograph, so it is not wise to rely on “that personal experience.”

We often find tables drawn up by some companies that produce photographic machines and films, the purpose of which is to determine the exposure factors, i.e. the definition of the diaphragm aperture and the shutter speed, which are suitable for different conditions when using a film of a certain sensitivity. These tables have been developed based on a study of some of the factors affecting the estimation of exposure factors. While these factors have a really great impact on estimating them, they are not inclusive of all the influences that play roles in estimating exposure. Therefore, they are usually set as a guide for beginners.

These tables overlooked an important fact, which is that the human eye is not a reliable measure for accurately estimating the power of light. Two or more people may differ in estimating the power of light in one circumstance, which leads to one of them estimating two exposure factors that are very different from what the other estimates. Therefore, we recommend using exposure meters. Exposure meters always, as it is a wrong economy to neglect purchasing an exposure meter when purchasing a camera, as it is sufficient (with the passage of time) to compensate for some of the value of the savings in raw materials that we would have thrown into the trash if the exposure meter had not been used.