The calibration process is an important part of the preparation for eddy-current testing (ECT) of different materials and the subsequent creation of identification methodologies, which need to be specifically related to certain probes. The paper describes an experiment focused on the preliminary study of Inconel 718 alloy, during which parameters of three selected probes are evaluated. The main objective is to obtain detailed information about the identification abilities of these probes for evaluated material. The standard penetration depth of eddy currents into the material is calculated based on the conductivity determined using the special conductivity probe, where was found that it is important to measure conductivity for a specific material before the ECT identification. The lift-off effect diagrams are interpreted for all three probes, which represent the base for the understanding of the identification abilities of used probes. Subsequently, suitability assumptions of probes for different applications are expressed.