Normally when one considers the intensity in the far field and how it scales with wavelength, a very quick and superficially simple answer is reached. Namely, the answer is that far field intensity scales inversely as wavelength squared, i.e., I(λ1)/I(λ2) = (λ2/λ1)2. Unfortunately, this relationship is only true for what is called the "on-axis intensity" of the central diffraction lobe. In most cases the interest is not to deliver a central intensity to the far field, but to deliver a maximum amount of power within a defined spot size in the far field. This spot size is normally defined to be within the first zero of the Airy pattern, or the exp (-2) point on a Gaussian intensity distribution. The purpose of this article is to examine how the far field average irradiance rather than on-axis intensity scales with wavelength, and how simple aberrations affect such average irradiance.