Physical size of full frame sensor vs iPhone pro sensor 

The physical size difference between a full-frame camera sensor and the sensor in an iPhone Pro is substantial.

Full-Frame Sensor:

A full-frame sensor is typically 36mm x 24mm in size. This format is the same as a 35mm film frame and is used in professional-grade DSLRs and mirrorless cameras. Its large size allows for better light collection, leading to superior low-light performance, dynamic range, and depth of field control.

iPhone Pro Sensor:

The iPhone 15 Pro, for example, has a much smaller sensor. The main wide-angle camera sensor size is estimated to be about 1/1.28 inches, which is approximately 9.6mm x 7.2mm. This is common in smartphones where compactness is essential. The iPhone uses multiple small sensors for its various lenses (main, telephoto, ultra-wide), and computational photography plays a big role in image quality.

Size Comparison:

Full-frame sensor: 36mm x 24mm

iPhone Pro sensor: ~9.6mm x 7.2mm (for the main camera)

So, the full-frame sensor is about 3 to 4 times wider and taller, making it vastly larger in surface area, resulting in significantly more light-capturing capability per pixel. This difference explains why full-frame cameras excel in image quality, particularly in low-light conditions, even though iPhone cameras are highly optimized for everyday use.