There is provided an arrangement for spot illumination (14). The arrangement provides an improved collimation and color mixing unit comprising a LED array (1), a convex shaped reflector (15a), a field lens (21) and an additional cylindrical reflector (15b) at the exit aperture of the system. In combination with an optical projection system which may comprise at least two additional zoom lenses and a gate (in which several maskers, gobos or shutters could be inserted) the system allows color mixing in an extended operational range including out of focus zoom settings often used to get soft edge spots.