I'm thinking about upgrading from an Olympus camera to the Nikon Z7 but already have a 30mm 1.4 Sigma lens which I'd like to keep and use on the Nikon as there are adapters available to buy. However, as my Olympus is a four-thirds camera and the Nikon is full frame I was wondering if this would affect the quality or aperture etc? Are there restrictions with using an adapter?