Sekonic's camera calibration
The Sekonic Digitalmaster L-758D meter offers the solution to variable ISO/EI ratings, and apparent sensitivity and contrast curves variations found in DSLRs. With a USB interface to link it up to a PC/Mac calibration program, the L-758D can remember three different cameras, two types of lighting (ambient or flash) and two measuring methods (incident or reflected) plus a range of ISO values for each of the cameras. There are twelve basic ‘profiles’ that can be stored, and within each profile a range from ISO 3 to ISO 8000.