Why people can't understand the 400D ought to match the P&S when
the 400D is used as a P&S (as it is designed for in these modes) I
don't really know. It is the same on all forums as well.
Until now, I have been keeping pretty quiet on this topic, I also have been struggling to understand and tame the XTI's conservative metering as a new user but your question leaves me yearning for an answer.
I think many people on this forum are using the WRONG camera. I am refering to those who were quick to respond to the OP with "do some PP" or "read a book and shoot in M". The XTI was not intended to be a professional tool to be shot solely in M mode. If it were it would have no AUTO settings. So they come from the perspective of accomplished photographers who found a pretty good top of the line amateur camera and start dumping on the rest of us.
Well I have news for you, Canon has marketed this camera to people who prefer to shoot in the Auto modes at least sometimes. Then they condenscendingly decided to NOT allow EC in the Auto modes. Well if that's your choice then it better produce pictures ready to print in the Auto mode. That's not an unreasonable expectation.
The 2 pictures the OP showed are unacceptable, even in Landscape mode, even if the subjects were in full shadow. Those 2 pictures are UNDEREXPOSED!
Having said all that AC1, my advice is to stick with the 400d, get it fixed if Canon will do it and gradually learn how to shoot out of the Auto modes.
As for your picture above, I believe your 2 subjects were in the shadow of the canopy. There are no shadows under their chins and under the lady's glasses as in the P&S picture. Therefore the comparison with the P&S shot is unfair. They are still underexposed, just not as much as if they were in full sunlight.
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Ex-Tee-Eye * Fifty mm 1,8 * seventeen-eightyfive mm 4,0-5,6