True for very large lenses where the dust and front element is sufficiently far and disproportionate to the aperture size! But for smaller cameras, especially

True for very large lenses where the dust and front element is sufficiently far and disproportionate to the aperture size! But for smaller cameras, especially cell phone cameras, that dust and smudge is magnified immensely and has a much much greater effect. The epitome of this effect is having dust directly on top of the sensor, which obviously is visible directly. Imagine how small your cell phone camera is: that dust is only a very short distance from the sensor, and it's not much better than being right on top of it. Dust on a small lens is also proportionately larger compared to the lens and the aperture. All in all, much greater effect. This article might as well not even apply to small cameras. Moral of the story: you should always clean your small camera lenses, and especially cell phone lenses! For larger lenses, the dust and smudge has less of an effect.