The iPhone camera is capable of shooting two aspect ratios---4:3 and 16:9. The 4:3 aspect ratio uses the full megapixels, whereas the 16:9 crops in for a wider view. We'll show you how to swap.
The difference between 4:3 and 16:9 is the width of the photo. However, it's not that simple on the iPhone. Shooting in 16:9 doesn't necessarily mean you'll get captured more from the sides of the shot. Depending on the cameras on your iPhone, it may simply crop the 4:3 photo.
Regardless, it's simple to switch between the two aspect ratios. First, open the camera app on your iPhone.
Now tap the arrow at the top of the screen.
Some controls will slide up from the bottom of the screen. Tap the "4:3" or 16:9" button.
Now you can choose "16:9," "Square," or "4:3."
That's all there is to it! Again, keep in mind that the 16:9 aspect ratio typically is a lower resolution than 4:3 since it's cropping the shot. If you want to always take full advantage of the camera hardware, shoot in 4:3.