How To Bench Focus a Source Four

Two concentric knobs may be found on the rear lamp housing of the unit. The Inner knob is used to move the lamp's position forward and backwards. The outer knob is used to adjust the lamp's position relative to the sides of the unit/reflector.

1. With the Source Four aimed at a flat surface, turn the unit on.
2. Using the knob located below the barrel, move the barrel forward or backward as necessary to achieve a hard edge on the beam.
3. Unlock and loosen (turn counter clockwise) the outer knob on the rear housing.
4. Gently move the outer knob as necessary - up/down, side to side - to center the lamp.
5. Tighten the outer knob (turn clockwise).
6. Turn the inner knob clockwise or counter clockwise to move the lamp forward and back which will result in the beam varying from noticeably darker in the center (hole in the center), noticeably brighter in the center (hot spot) or virtually even or flat. In general, for most purposes a flat field is desirable.