Lens arrays are common in many standard lighting products. We present some instructive models to predict lens-array performance and demonstrate the effects of lens arrays with various tilings. In some cases the beam intensity can be approximated by the convolution of the source intensity with the lens-array intensity response (e.g., lens intensity using collimated illumination). In more complex cases, the beam intensity can be approximated by the superposition of the source intensity convolved with each lenslet's intensity response. We demonstrate this effect using Monte Carlo ray-trace simulations for both uniform- intensity sources and nonuniform-intensity sources such as a lamp in a parabolic reflector.