Searches for charged Lepton Flavor Violation in the muon sector require specialized detector technologies for reconstructing particles of relatively low energy with extreme resolutions. For $\mu \to e \gamma$, the detection of signal photons with 52.8~MeV energy from muon decays at rest can be performed with high efficiency and good resolutions using calorimeters. However, when very high muon beam rates are available, reconstructing with a magnetic spectrometer the $e^+e^-$ pairs emerging from photon conversion can be a valid alternative. I will review here the pros and cons of the different techniques in view of future $\mu \to e \gamma$ experiments.