A group of dedicated wildlife photographers has tested the new Falcon 300mm telephoto lens. With it, they were able to capture stunning images of birds that were only seen as blurry shapes with their 200mm lenses, even though the 200mm lenses, with their larger apertures, allow more light to enter than the 150mm Falcon lens. Based on these photographers' experiences, any serious wildlife photographer should choose the Falcon lens if they are purchasing a lens for bird photography. Which one of the following most seriously weakens the argument?