The RF mount is wider than EF, though the older lenses can still be used with Canon’s newer cameras thanks ... RF lenses come in two types. There is RF itself, which produces an image circle ...

The lens in question was a Sigma 15-30mm f/3.5-4.5 EX DG, built to work with a Sigma camera using the SA mount. As it turns out, the SA mount is actually based on the Canon EF mount, using the ...