It's not known if they used the beefed up camera on the 4S or not, but in an interview with the Irish Film & Television Network, Oscar-nominated cinematographer Seamus McGarvey admitted that he filmed a couple of shots for The Avengers using an iPhone. And while he hasn't specified which were captured with what we're assuming was the iPhone 4, they apparently even appear in the first trailer that was released last week.
When asked if he had any advice for aspiring cinematographers when it came to equipment, he was quoted as saying:
"The beauty of photography or cinema is that you make every choice based on the content at hand. On The Avengers, I did a couple of shots on the iPhone and they are in the movie. In fact, they are in the trailer! I understand that sometimes there is no choice and you have to go for the cheapest option, but if you are limited for choice, you can still make poignant decisions that will effect the look of the film..."