The simplest system is to use a lens set at the hyperfocal distance.
Martin reached up to adjust a small lens set in the roof of the cabin, then glanced over his shoulder.
He looked more closely and found a small jewel-like lens set in the metal.
But the most fascinating thing about the figures was undoubtedly the large glasses with lenses set at an angle.
Or it is a gargantuan lens set in the sky.
We use two, their lenses set at different angles for a binocular effect.
The weapon was a six-foot black tube with a red lens set in one end.
Another lens, set into the door near its very top, was there to let the precious flameless torch shine out.
T'Pol moved quickly through the house to the foyer and peered outside through a small optical lens set in the door.
The typical noon-mark sundial was a lens set above an analemmatic plate.