EOS 550D: Could someone please explain me this?

[askoric]

Hello everybody!
I am new to the world of photography so there is probably an easy explanation for my troubles.
What confuses me is that I took two pictures in full manual mode, one with flash, the other without, and they don't have the same exposure in the areas the flash couldn't possibly reach. I was sitting in a cafe and took a shot at the islands in front of me, then I did the same thing but I also popped up the built-in flash. The picture with the flash is brighter. There is no way the flash could have reached the islands
The same shutter speed/apperture. The same ISO. Same WB as well. Center spot metering. Auto Lighting optimizer off. Periferal luminance correction off. What gives?

When I look at the exif data from IrfanView, it claims to be "center weighted metering" and "auto WB" which is not the case, the camera is definitely set for spot metering and Daylight WB (I can reproduce).
The photos (shrunk in size and saved as jpg) are attached.
Please help me solve this mistery

[audiman90]

I would suggest that the first picture was taken with the centre spot metering just above the horizon on the light coloured sky and the second metered on the land or the sea.

[OsmosisStudios]

If it's the same shutter speed/aperture/iso, then there's no reason for those images to be different. I'd double-check: they cant be the same.

[askoric]

Thank you for your reply audiman90!

The camera was in full manual mode (M) so I don't think that was the case...
The spot the light metering was done for would only affect the reading of the camera's built-in light meter, but it wouldn't change the shutter/apperture/ISO ratio. Not in "M" mode, anyway.
So in that mode, the light meter has the function to tell the photographer that he is too light or too dark, nothing more. Am I mistaken?

Any other ideas?

[askoric]

Thank you OsmosisStudios!

You were spot on! Thank you for making me go through the exif info again, as well as confirming my knowledge about exposition (I am new to all this ).

Even though I was in M mode, and didn't change the shutter speed, by popping up the built-in flash, the camera changed the shutter speed down to 1/200.
I am guessing that is the fastest sync speed for the shutter and built-in flash.
Still, I wish the camera would let you make that error and not change your setup.

Thank you all for your quick replies!