Olympus E-20N - Manual (Page 74)

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To focus the subject and blur
the background, select a
small aperture value for a
large aperture. To focus the subject and the
background, select a large
aperture value for a small
aperture.
Setting the Aperture Value ( A Mode)
With the mode dial set to A (Aperture priority mode), you can select the aperture value
for your shots. Because adjusting the physical size of the aperture determines the
amount of light allowed to enter the camera through the lens, the aperture setting
expresses the actual size of the aperture. It is important to remember, however, that the
smaller the value of the aperture setting, the larger the diameter of the aperture, and
conversely, the larger the value of the aperture setting, the smaller the diameter of the
aperture.
Opening the aperture not only allows more light into the lens to compensate for low light
conditions but shortens the depth of field as well. Use a large aperture to focus only the
subject and blur the background when you want to shoot a portrait. On the other hand,
use a small aperture to focus both the subject and the background.
Fine adjustment of aperture and shutter speed
If the brightness is adjusted with fine adjustment of the aperture value, in some cases it may appear
that the shutter speed drive is not adjusting shutter speed. The displayed aperture value is the value
of the optical aperture, and the shutter speed is calculated based on the CCD’s sensitivity to the
brightness of the light to determine the optimum exposure. In order to achieve this, the aperture
value and shutter speed may occasionally appear not to be adjusting in fine increments and does
not indicate a malfunction of the camera.
Bright spots in the picture?
If you see extremely bright spots in your images caused by sunlight or reflected sunlight, this is a
phenomenon called “smear” which occasionally occurs with digital cameras that employ CCDs. To
avoid this problem, compose the picture again and try to eliminate the bright light, use a smaller
aperture, or use a Neutral Density filter.
Large Aperture (f2.4) Small Aperture (f11)