Praktica FX2 - Focusing and Diaphragm Control; Focusing Method; Diaphragm Aperture Explanation

Focusing
is performed by means of the distance-setting ring on the lens mount. This ting has to be
turned to the left, or to the right, until the image on the ground-glass screen appears perfectly
sharp. During focusing, the lens should be set at full aperture. When using the sports finder,
you may either focus beforehand on the ground-glass, or set the distance adjusting ring to an
estimated, or measured range.
The Diaphragm
is adjusted by means of the diaphragm ring. The small numbers indicate wide lens apertures,
whereas the large diaphragm numbers refer to the smaller apertures. The volume of light
entering the camera through the lens can be regulated by the diaphragm. Large diaphragm
apertures permit short exposure speeds, small apertures require longer speeds. The next dia¬
phragm number upwards on the scale makes it necessary to double the exposure time.
Besides, the diaphragm is a primary means of regulating the depth of field in relation to the
various distance settings, as may be seen from the chart on page 7 .
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