Samsung UN46ES7500FXZA E-Manual page 639

The 3D images don't look quite right.
The ideal viewing distance is three
times or more the height of the screen.
We also recommend sitting with
viewer's eyes on a level with the
screen.
The batteries in the 3D glasses don't last
Turn off 3D glasses while not using
them. If you leave 3D glasses on,
battery lifespan is shortened.