First of all, the word "fresnel" is pronounced with the s being silent, more like "fra-nell."
Fresnels, along with ellipsoidals, are the real work horses of stage lighting. While most ellipsoidals are used FOH (Front of House, i.e., over the audience), most fresnels are hung on electrics (pipes over the stage, wired with electrical circuits). Fresnels have several important characteristics:
1. The small reflector behind the lamp and the special lens (with concentric rings on the outside and a pebble finish on the inside) produce a very soft, diffused light.
2. Since the light does spread quite wide when exiting the instrument, fresnels are mainly used quite close to the stage. For example, when hung on an electric over the stage, the throw distance is only about 20 feet.
3. Fresnels have very limited focusing capabilities. Without some accessories mentioned on the next slide, the most we can do is move the lamp back and forth to somewhat widen or narrow the spread of the light.
4. As with lekos, gel held in a gel frame can be slid in front of the instrument to color the light exiting the instrument.
