Draw an image of a lens facing a sensor or film frame.  Make the sensor larger or smaller, the film larger or smaller.  Make the sensor or film several sizes within the largest.   The lens gives what it does. The frame size accomodates more or less and that is it..essentially.  What comes from the lens is the same.   

When I shoot a 30mm and get a 45mm frame, I get all the problems of the wider angle lens..though with this lens, the problems have not been apparent compared to some other brands.   Enough from me..I repeat myself.        Tom.