Night Pictures

shivagarwal

I'm new to this forum and the world of DSLR's. I recently bought a D3100 and used it to click night pictures using a tripod. Since I was new to DSLR's I didnt try the manual mode but stuck to the night mode. While clicking a picture of the Eiffel Tower in night mode the tower was perfect, but when I clicked my wife and myself using the timer the background was clear and we appeared blurred.

I'm looking for help on what would have caused this and which settings should I focus on to get better night pictures.

Regards,
Shiv