Pentax K-7 Operating Manual page 42

Model characteristics Page
Lets you capture images that require slow
B (Bulb) shutter speeds such as fireworks and night p. 110
scenes.
The shutter speed is locked at 1/180
X (Flash X-sync Speed) seconds. Use this when using an external p.112
flash that does not automatically change the
shutter speed.
_' (Movie) Use this to record movies, p. 163