The discussion focuses on converting between wavelength and frequency in resonators, specifically addressing how to find the frequency linewidth Δν from a given wavelength linewidth Δλ. The relation Δλ/λ = Δν/ν is confirmed as correct, indicating that the percentage error in wavelength corresponds to the percentage error in frequency. A user inquires about calculating the separation in wavelength for a resonator with a specific length, noting that the previous equation is not applicable in this context. The Free Spectral Range is mentioned as a critical factor, with a specific example of 50 THz separation for a resonator length of 3 microns. Understanding these conversions is essential for accurate measurements in optical resonators.