I noticed a strange thing when locking "AF only" with the AF/AE-lock button. I thought that when locking focus that way you should still be able change aperture values by turning the aperture ring (in A or P mode) but that doesn't work. Of course shutter speed changes when I recompose, but I cannot change the aperture itself. Even stranger is that when locking focus in S mode the shutter speed can be changed. ??? Is that normal or is there a problem with the camera? I have never experienced that on other cameras.