Slide film is different from either color or black and white negative film in that slide film creates a positive image. Also known as reversal film, slide film is less forgiving and has a narrower latitude of exposure than negative film, making it tricky to expose as less information will be captured in the event of an error. In exposing slide film, it is important to expose with care for the highlights, as it is easy to overexpose the sensitive film.
Load the slide film into the camera and set the film speed (ISO) setting to the proper setting. Many cameras have a small holder on the back of the body for holding the end of the box the film came in, which has important information on it, such as film speed and the number of exposures.
Using the in-camera light meter or a separate, hand-held meter, measure the reflected light of the scene by pointing the meter at the subject. The best way in which to do this is to point the meter at a highlight or white part of the image and note the reading, then do the same for a shadow or dark part of the image and take the average of the two.
If your image has many light areas, it is possible to "fool" the light meter. Stop down by one f-stop or increase the shutter speed to preserve the highlight details, if necessary.
Expose your image by pressing the shutter release button.