If you knew a few things about the 5D MkII evaluative meter, its balance and weighting, you'd run quickly to a hand-held meter. It is accurate as an integral camera system, not a comparative one. You would be much better learning metering with something like the Olympus OM4 and its variants, coming to grips with multispot metering, hightlight and shadow bias, additive metering and subtractive metering. The MK III FYI uses additive metering as part of a large algorithm designed to respond to key image criteria (digital lightmeters can often now be calibrated as additive, subtractive or mean in their measurements). In other words, the camera is working as a system against you, not in your favour, only insofar as committing the image to film after accepting what the meter says is gospel. Certainly, they have no capacity to measure critical, individual luminances of a scene that is so much a staple of refined traditional photographic metering technique.