Pentax K10D Operating Manual page 162

160
Using the M (Flash X-Sync Speed) Mode
The shutter speed is locked at 1/180 seconds. Use this when using an
External flash that does not automatically change the shutter speed.
1
Set the mode dial to M.
4
• Turn the rear e-dial to adjust the aperture value.
• Press the Green button to retain the shutter speed at 1/180 sec and
automatically adjust the aperture.
• When the sensitivity is set to [AUTO] and exposure mode is set to M (Flash
X-sync speed) mode, the sensitivity is the lowest sensitivity set in "Setting the
Range of Automatic Correction in AUTO" (p.140).