Dell 1610HD - Manual (Page 28)

28 Using Your Projector
22 Auto adjust Press to synchronize the projector with the input
source. Auto adjust does not operate if the OSD is
displayed.
23 Zoom + Press to increase the image.
24 Zoom - Press to decrease the image.
25 VGA Press to choose VGA source.
26 Video Press to choose Composite Video source.