wahh...thanks all for the replies once again

n sorry for repeating myself earlier :embrass:
hope this is not a silly qn but...leading on from above....
exposure consists of the aperture opening (amount of light entering), shutter speed(time allowed for light to enter in) and ISO (determines the sensitivity of the sensor to light)...if choosing one of the modes say aperture control or shutter speed control, the camera automatically selects the other one for
'correct exposure' -- based on what the camera thinks from your metering setting (average metering, spot metering etc)
is this correct? if so, that means
full manual is you select everything yourself (so the half press on the shutter release is just a focus lock and not a focus+exposure lock)
thanks! :bsmilie: