Pentax K-x Operating Manual page 102

100
Using the a (Manual) Mode
You can set the shutter speed and aperture value. This mode is suitable
to take pictures of your choice by combining them. This mode is
convenient for taking pictures using the same combination of the shutter
speed and aperture settings or taking intentionally underexposed (darker)
or overexposed (brighter) photographs.
1 Effect of Aperture and Shutter Speed (p.88)
1
Set the mode dial to a.
4
2
Turn the e-dial to adjust the
shutter speed.
The shutter speed can be set within the
range of 1/6000 to 30 seconds.
3
Turn the e-dial while pressing
the mc button to adjust the
aperture value.