Nikon D300 - Manual (Page 269)

243
Q
A
Video Mode (pg. 313)
Be sure that the video standard matches the standard used in the video
device. Note that resolution will drop when images are output on a PAL
device.
A
Television Playback
Use of an EH-5a or EH-5 AC adapter (available separately) is
recommended for extended playback. When the EH-5a or EH-5 is
connected, the camera monitor-off delay will be fixed at ten minutes and
the exposure meters will no longer turn off automatically. Note that the
edges may not be visible when photographs are viewed on a television
screen.
A
Slide Shows
The [Slide show] option in the playback menu can be used for automated
playback (pg. 252).