An air filter has a filter housing with inlet opening, outlet opening, and service opening. A first filter element and a second filter element are arranged inside the filter housing between inlet opening and outlet opening. The first filter element is arranged in a mounting frame. The first and second filter elements can be flowed through serially in one or more operating states of the air filter. The mounting frame is insertable through the service opening into the filter housing in a joining direction and removable from the filter housing opposite to the joining direction. The second filter element has a wedge stop. A clamping wedge arranged at the mounting frame, upon insertion of the mounting frame into the filter housing, contacts the wedge stop of the second filter element and clamps the second filter element at the filter housing in a clamping direction transversely to the joining direction.