CHOOSING AN APPROPRIATE ISO SETTING
You must first consider the mission requirements. For each mission there are one or more factors that must be considered. Sometimes one factor offsets the other, or one may have an opposite effect on the other.
You should choose an ISO setting that will take the desired picture. The slower-ISOs will give you comparatively better grain and resolving power. Range of f/stops and shutter speeds available under the lighting conditions also dictate your ISO choice. For example, a portrait is normally shot with a wide aperture to reduce depth of field. Choosing a high ISOs for an outdoor portrait on a sunny day would limit you to fast shutter speeds and small apertures. Conversely, in low-light situations where wide exposure latitude is needed or on an airborne mission where fast shutter speeds and small apertures are desired, a high ISO is ideal.
Let's take a look at some examples and discuss how one would consider ISOs for different situations. Remember that these are hypothetical situations and are not meant to be exact solutions for that example.
For most newspaper and magazine work, the best choice is a ISO. In this situation, grain is not as important a factor since there will be a loss of print sharpness when it is reproduced in the newspaper or magazine.
Design: David L. Heiserman
Publisher: SweetHaven Publishing Services
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