The
zoom
profile-spot employs a variable-lens system which enables variations in the
beam
angle while maintaining the ability to generate a sharp or soft
image
at any size.
The
lens
system of variable
lens
profile-spots consists of two lenses which can be moved forward and backwards independently of each other.
Different
beam
angles are produced by adjusting the distance between the two lenses, which changes the focal length of the
lens
compound. The
distance of the
lens
closer to the gate from the gate determines the sharpness or softness of the
beam
of light.
The versatility of
zoom
profile-spots is somewhat offset by a reduction in optical efficiency, as well as an increase in unit length and weight, compared to a fixed-angle profile-spots of similar wattage. Some
zoom
spots employ condenser optics to improve their performance. Variable
lens
profile-spots are available in the
wattage
range of 650 to 2500 watts, with typical
beam
angles of 9/15, 12/22, 18/32 and
