i'm pleased that the 5D2 microfocus remembers the combination of lens and extender (and pleasantly surprised that it remembers non-canon lenses, aparently by focal length)
however, resolution seems to be proportionally more degraded by the use of the extender than with other bodies -- and the focus interaction of the extender varies from lens to lens. that is, the same extender requires a plus correction on one lens, but minus on another
what's going on?