Exposure Bracketing

I took a series of images one under exposed (-2 EV), one neutral exposed(0 EV) and another over exposed (+2 EV). I could see the differences when I took photos outside at night. Unlike the ones taken during the day, over exposed one looks like more properly exposed than the neutral exposed one.

Neutral exposed (0 EV)

Under exposed (-2 EV)

Over exposed (+2 EV)

These are another series of images at aperture of f/3.5, shutter speed of 1/30th of a second with different ISO settings. The aperture and shutter speed are staying the same, however, as you can see the information on the right side of the photos, ISO is changing to create those under and over exposed images. My first properly exposed image is made at ISO 800.