>>3051797Sigma made a mistake with the flange length of that camera. It's basically 44mm DSLR length flange, but without the advantage of the mirror.
They should have made it shallow like E-mount, then their camera would be compatible with every new future optics designed for E-mount.
Right now they have gone against their own camera, and are making new special lenses just for Full Frame E-mount, and those new lenses will not even be compatible with their own SA-mount.
It didn't have to be this way... Now they end up designing lens for competitor against themselves.