According to MacRumours, who saw the schematics, there will be some changes to the camera housings on the rear of the iPhone 13 models, as well as the overall thickness of the devices.
It's claimed the iPhone 13 and 13 Pro models will be 7.57mm thick, compared to the 7.4mm thickness of the iPhone 12 models, while the camera housings are said to go from around 1.5/1.7mm to 2.51mm on the iPhone 13 and 3.65mm on the iPhone 13 Pro.
The report says the increase in thickness to the camera bumps is to stop the lenses from protruding as much as they do on the iPhone 12 models, allowing a more seamless finish. It's also said the camera housing in general will increase in size on all models though.
MacRumours claims the iPhone 13 models will see a camera housing measuring around 29 x 29mm, while the iPhone 13 Pro models is said to be 36 x 37mm, which is said to be around the same as the current iPhone 12 Pro Max.
Other rumours surrounding the iPhone 13 models have suggested we will see some camera improvements, like sensor-shift stabilisation coming to more models. It's also thought the iPhone 13 models could come with a smaller notch and there has been some talk of ProMotion displays. You can read all about the iPhone 13 rumours in our separate round up feature.