Pentax K100D User Manual - Page 148

146 About the L Button The aperture and shutter speed are automatically adjusted to the appropriate exposure at that moment if the L button is pressed in a (Manual) mode. You can choose from the following three adjustment methods in [AE-L bttn on M expsr] in the [A Custom Setting] menu. 1 Program Line The aperture and shutter speed are adjusted automatically. 2 Tv Shift The aperture is locked and the shutter speed is adjusted automatically. 3 Av Shift The shutter speed is locked and the aperture is adjusted automatically. Shutter speed is adjusted to appropriate exposure according to lens aperture when lens aperture is not set to s position. 1 Notes on [Using Aperture Ring] (p.188) 5 Using the p (Bulb) Mode This mode is useful for the long exposures required for shooting night scenes and fireworks. The shutter remains open as long as the shutter release button is kept pressed. 1 Set the mode dial to p. Function Reference • Turn the e-dial to adjust the aperture value. • Set the aperture value in increments of 1/2 EV or 1/3 EV. Set in [Expsr Setting Steps] in the [A Custom Setting] menu. (p.148) • Use a sturdy tripod and the cable switch CS-205 (optional) to prevent camera shake when using p (Bulb) mode. Connect the cable switch to the cable switch terminal (p.15). • Bulb shooting is available when using the remote control shooting mode (p.64). The shutter remains open as long as the optional remote control's shutter release button is held down. • Noise reduction is a process to reduce noise (image roughness or unevenness) caused by low shutter speed. Set in [Noise Reduction] in the [A Custom Setting] menu. (p.106) • When in p (Bulb) mode, the sensitivity is equivalent to ISO 200 when sensitivity is set to [AUTO].