PTP

Picture Transfer Protocol

PTP (Picture Transfer Protocol) is the standard protocol cameras use to transfer images and accept commands over a USB connection, without needing vendor-specific drivers.

PTP is the language a camera speaks to a computer or phone over USB. It lets the connected device list the photos on the camera, download full-resolution files, and in many cases trigger the shutter and read settings — all through one standardised protocol.

Because PTP is a standard, a tethering app can talk to Canon, Sony, Nikon and Fujifilm bodies over the same USB foundation, layering each vendor's extensions on top for camera-specific features.