English: Various scanning modes used in Scanning Ion Conductance Microscopy. A, constant-z-mode: The probe is scanned at a constant z-position and the distance to the sample is reconstructed from the current. B, DC or constant distance mode: The probe is approached until a predefined threshold resistance is reached. The probe is then moved laterally and the distance between tip and sample is maintained by a feedback system. C, AC-mode: The probe position is additionally modulated sinuusoidally, instead of the direct current signal, the changes in amplitude of the alternating current component are used as the feedback signal. D, backstep or hopping mode: The probe is advanced towards the sample surface at every single pixel. This is a rearrangement of the Figure 4 from Happel et al.: Sensors 12, 2012 doi:10.3390/s121114983