In the original published article, our implementation of the Gillespie algorithm for channel gating simulations contained a minor error. We resolved this error and repeated the gating simulations. This correction comprises updates to the following: Charge detection threshold in tethers expressing GCaMP8f (Results and Discussion, Figure 5 caption) Figure 5D, E; Figures S7B–D and S8A, B Supplementary Note 3 Figure 5 Figure 5.