22 EXPOSURE COMPENSATION
Note
When it is difficult to determine exactly how much correction to make, bracket the exposure. using any of the three methods.
4. ”Pushing” the ISO Rating
There may be occasions when, due to insufficient lighting, you are forced to use undesirably slow shutter speeds. In this case, you can ”push” the ISO setting on the camera to a higher value. Usually this is done by multiplying the normal ISO film speed by a multiple of two, such as two or four. The entire roll of film must be shot at the ”pushed” ISO setting; otherwise, exposure will not be correct for all frames. It is also necessary to inform the developing lab of the change in the ISO rating or the film will be incorrectly developed. Hbwever, since not all films can be ”pushed” with acceptable results, it is recommended to read the film data sheet or other photographic literature before you try this technique.
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