Hello Boyen, and welcome to the friendly Camera Labs forum!
To enjoy your stay here please have a look at the house-rules
When shooting in M(anual) mode the exposure compensation does not influence the exposure but simply the exposure-indicator: Changing the exposure accordingly has to be done by you.
Here's an example: say you have 0EV exp.comp. dialed in and the scene is perfectly exposed at ISO 200, f/5.6, 1/250 sec, so you set these values. Now dial in a -1EV exp.comp. and the indicator will now tell you that you need either to stop down to f/8 or shorten your shutter to 1/500 for the exposure*. That is exactly 1EV less exposure than without exp.comp.! But: You have to change the shutter from 1/250 sec to 1/500 sec (or close the aperture from f5.6 to f8) all by yourself to comply with the "advice" of the exposure-indicator. After that you get the slightly underexposed images and all is well and as it should be
* This is a bit over-simplistic. The exposure-indicator simply says: "With your current settings you're gonna overexpose your image by 1EV - so act accordingly"
Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews
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