The phone’s camera hosts the biggest improvements. While both phones have a 12 MP camera with a f/1.8 sensor and a six-element lens that is 60% faster and 30% more efficient than its predecessor, the iPhone 7 Plus also has a dual rear camera that allows for a shallow depth of field, 2x Optical Zoom and 10x Digital Zoom support.
It will essentially allow you to take those DSLR-Like photos that have the subject in focus with the background out of focus. This feature will be made available later in October through a software update for the iPhone 7 Plus.
Apple increased pixel size to 1.5µm (from 1.4µm – those measurements are in micrometers) and kept the pixel count the same by using a 15% larger sensor. 8MP iPhone 5s can give you a [square route of 8 is 2.8284: 10 x 2.8284 = 28.28427] 28cm long, or [4 x 2.8 = 11.3136] 11in long shot.
In comparison, a 13MP phone camera could give you [square route of 13 is 3.6055: 10 x 3.6055 = 36.055] 36cm long, or [4 x 3.6055 = 14.422] 14in long reproduction of your shot.”
Both the iPhone 7 and iPhone 7 Plus have upgraded cameras. iPhone 7 has a 12 megapixel sensor that is claimed to be 60% faster. iPhone 7 also has a quad-LED flash with 50% light output, and can detect for the imperceptible flickering of energy efficient lights. Each camera on iPhone 7 has a different focal length, allowing users to pick between shooting photos with a wide-angle or a telephoto lens. The iPhone 7 Plus will also be able to do some software tricks using those two different focal lengths.
It is worth noting that while the iPhone 7 features a single 12MP rear camera, the larger screen variant comes with two 12MP rear camera with 2x optical zooming capability upto 56mm. Both sport a 7MP FaceTime camera for selfies and video chats.