Disadvantages of LED instruments
LED instruments cannot be used to create a hard edged beam, which is needed for gobos and other effects which require the use of an ellipsoidal reflector spotlight. Because color mixing is done using three or more colors of LEDs, mixed colors will have multiple edges to shadows where different colors are showing, however Elation Professional has introduced instruments that group three LEDs behind a single lens to make the multiple shadow lines less noticeable. Because of the multiple light sources in the fixture, most shadows are a soft edge as well.
As of 2008, the output intensity of LED lighting is still unable to match the luminous power of traditional incandescent lamps. A 300 watt medium-spot GE PAR-54 easily outshines a PAR-64 RGB LED Pro fixture from American DJ, which is one of the brightest LED fixtures available in 2008. The LED output spectrum is additionally very cold (blue) compared to the warm (yellow/red) of the incandescent.
Several times as many LED fixtures may be needed to match the brightness of a traditional fixture of similar size. But LED fixtures also currently cost several times more than a traditional incandescent fixture, greatly increasing the expense to use LED fixtures at the same brightness level as with traditional incandescents.