We demonstrate the feasibility of field mapping with proton beams having kinetic energies between 1-2 Megaelectronvolt. Adjustment of the ultrafast (40 fs) laser driven TNSA mechanism delivers a nearly pure proton beam with a low transversal emittance and an emerging broad kinetic spectrum. Suitable electronic image detection allows tracing of the temporal field evolution with temporal snapshots. An increase by a factor of more than 8 of the proton drive efficiency in terms of laser energy consumption has been achieved with thin foil targets (400 nm) when the temporal laser contrast was enhanced to 10 orders of magnitude by means of a double plasma mirror.