Question: what is the difference between e mount and fe mount?
Answer: The E mount cameras can be APS-C or Full Frame. FE is used to nickname E-mount lenses that support a full-frame sensor. e.g. SEL28F20 is nicknamed FE28, to describe it as a 28mm Full Frame lens for E-mount. and SEL24F18Z is nicknames E24Z, to describe it as a 24mm APS-C lens for E-mount with Zeiss label.