Pentax K-R Operating Manual page 23

2
Stop the slideshow.
Slideshow ends when one of the following operations is performed
during playback or pause.
- the four-way controller ('v) is pressed "1
- the I-_ button is pressed "1
- the MENU button is pressed "1
- the shutter release button is pressed halfway or fully *2
- the mode dial is turned *2
- the AF/AE-L button is pressed *2
"1 After slideshow ends, the camera switches to normal Playback mode.
*2 After slideshow ends, the camera switches to Capture mode.
For movies, only the first frame is displayed and then the next image is
displayed after the set interval has elapsed. To play a movie during a
slideshow, press the OK button while the first frame is displayed, After the
movie has finished playing, the slideshow will resume.