Just regarding the metering differences between the same body metering with an EF lens
and metering with an MF lens (with no electrical coupling)...
Make a test ... put an EF lens on the body select wide open aperture ... focus on a scene,
disengage AF (just to have a comparable and reproducable starting point) ... now
meter with the different metering modes (matrix, partitial ... spot) ... and then ...
unlock the lens and screw it a few degrees as if you would like to take it of the body ...
just enough that the electrical coupling no longer works ( the body will now show f/00)
... it now behaves like an MF lens ... but it is absolutely the same lens that you had used
before ... meter again with the same modes as before ....
with my 50L I get up to 1.5 stops difference depending on metering mode.
and metering with an MF lens (with no electrical coupling)...
Make a test ... put an EF lens on the body select wide open aperture ... focus on a scene,
disengage AF (just to have a comparable and reproducable starting point) ... now
meter with the different metering modes (matrix, partitial ... spot) ... and then ...
unlock the lens and screw it a few degrees as if you would like to take it of the body ...
just enough that the electrical coupling no longer works ( the body will now show f/00)
... it now behaves like an MF lens ... but it is absolutely the same lens that you had used
before ... meter again with the same modes as before ....
with my 50L I get up to 1.5 stops difference depending on metering mode.