I have just changed the focusing screen; something I have done now a few times. Now "normal" metering does not occur in auto or manual focus. In live view all ok. Using the eyepiece produces exposure times of minutes rather than fractions of a second! Changing EV doesn't seem to be of use.
To attempt to work around this problem I have a changed lenses, taken the memory card and battery out for 30mins, and reset to factory settings - all to no avail.
I have read somewhere that there is an eye piece light sensor? If there is is it blocked and how do I find it?