Nikon SB-27 - Manual (Page 15)

Adjusting the flash head
15
The flash head rotates from the horizontal to the vertical
position along a 180° arc. From the horizontal position,
simply tilt the flash head up 90° until it clicks into position.
Keep the flash head in the horizontal position for normal flash
shooting.
• When the flash head is set to the left as viewed by the
photographer, a shadow falls to the right of the subject, and if
the flash head is set to the right, the shadow falls to the left.
• When the flash head is set in the vertical position, the shadow
appears under the subject's chin or just behind the subject, as
the flash illuminates the subject from the top.
—This flash-head adjustment capability makes multi-directional bounce
flash operation possible. (See page 49.)