Hi! I have a question about the lens aperture. It seems that the lens aperture blade is like adjusting by itself? At first I thought it is because I were using shutter priority but when I use other mode, the aperture changes itself (I mean technically, not digitally/ when I take photo). I mean when I set the aperture let's say 2.5. Then I swing the camera, the aperture blade is buzzing, it closes down and/or opens wide automatically. I know this is not affecting the photo because when I hit the shutter button the results still use my aperture setting. Maybe someone can explain this to me?