As you know iOS 4.1 has introduced HDR camera feature for iPhone 4. When I went to the opthalmology for eye exams last week. The doctor's office is 7th floor at the building where is in front of Union Square. I have taken some picture using HDR. It seems good example to show the performance. At each photos, the left is original, the right is HDR.
Please take a look at the sky part. The original picture completely became a white but HDR one has blue sky! The dark part was also recovered.