i've had some troubles with this. when i do really close up macro with my f3 (i reverse my 28mm lens, and it is suprisingly close actually) i always get shots that are very pale and almost like there is a screen over it. none of my other shots do that. I was thinking maybe (since i hold it and i dont have a reverse mount) that it was light leaking in. But i dont see how, there are like barely any cracks between the lens and the camera, and even those are tiny. I really like macro, so i'd like to know how to fix this.