Took a long night exposure and played around with different adjustments with two different results with either Auto Levels Separate or Auto Levels Combined settings as explained here:

http://support.apple.com/kb/PH7569

http://support.apple.com/kb/PH7568

So here are the resulting pictures:

https://picasaweb.google.com/116772938291334918131/ApertureAutoLevels

I like the darker picture and it’s more like the scene I recall shooting, though the color of the towers look more saturated, when compared to the other night shot and the day shot.

The only issue is, the darker night shot seems to have more noise, especially in the sky.

Is that expected?  The difference in the two settings is very subtle on day shots but really pronounced in this night shot.

The grain in the sky of the Auto Levels Separate (the darker shot) puts a damper on what otherwise is a good result.