In the previous lecture we saw that the low-pass filter corresponding to coherent imaging was given by the pupil function, while the LPF for incoherent imaging with the same system was given by the autocorrelation function of the pupil. Some comparison is in order. First of all, the frequency where the OTF goes to zero is twice the frequency where the CTF goes to zero, meaning that higher spatial frequency fields can make it through the system. However, for binary pupils, the pass band of the CTF is generally flatter than the pass band of the OTF, meaning that the frequencies that do pass retain better contrast. These issues and more make comparison of the two types of imaging difficult.