An optical system that behaves like an integrated low pass filter with an adjustable optical cutoff frequency. The filter behavior is “integrated” in the sense that the overall design of the optical system results in the low pass filter characteristic, rather than having a separate, discrete component that implements the low pass filtering. The filter behavior is “adjustable” in the sense that the optical system can be adjusted in a manner that changes the optical cutoff frequency of the MTF. For example, moving certain optical components within the optical system may cause the change in cutoff frequency.