[Leica] Canon 5D + Leica Lens Exposure Question

[dmdorn_ct_usa at mac.com (David M. Dorn)]

If the chip in the camera lens adjusts to compensate for proper 
exposure as in the example given, 400ASA to 200ASA, doesn't this point 
to the fact the the Cannon's touted "low noise" is really somewhat 
hyped?  If I set my ASA to 400 but the camera is really using 200, then 
I would expect the noise to be less.  I assume one could test this by 
making reading with an incident meter of a test card and then compare 
the camera's exposure setting with the meter's reading.  I would do so 
but I still only shoot film :-)

Regard,

David