Recent experiments with my Sony NEX-5N and sunset have revealed that the ISO setting can greatly change the result of an image. Of course, post processing can clear many of the color and brightness issues up, but keeping it pure and matching what you "see" is the goal.
Here are two recent images taken of the same sunset. Each image is 1/60th of a second with the lens at F/4 and a 0.48x 58mm attachment.
|ISO 640 - Sunset mode|
|ISO 500 - "Intelligent mode"|
|ISO 1600 - 1/400 F3.5|