I know that ultimately the photographer is responsible for the end image but I think the lens and camera has a lot to do with it as well. Especially in the digital age when the sensor, processing engine etc differs from camera to camera, it really does make a difference. For instance, Panasonic images tend to be cool, Olympus have a great blue tone to their images and Sigma don't know any other colour exists except yellow. That might be a bit harsh but that's the way I see it.