Apple’s iPhone is fast becoming the go-to camera not just for smartphone users, but for the point-and-shoot crowd, too.According to the latest usage data from Flickr, the iPhone 4 is the most popular camera on the photo-sharing service, surpassing not just the Canon EOS 5D Mark II, but the Nikon D90, Canon EOS Rebel T2i, and Canon EOS 7D, as well. No small achievement, considering Flickr’s 51 million registered users and the reputations of the competition. Which is not say that the iPhone matches any of those cameras in photo quality, just that it’s the tool of choice on the top photo-sharing site on the Web.And that’s among both cameras and phones. The four most popular camera phones on Flickr currently? The iPhone 4, iPhone 4S, iPhone 3G and the iPhone 3GS — in that order.