I've been somewhat confused by the M. I think I have it in Aperture priority with auto iso and yet even though I set the aperture at 1.4 it displays a variety of f stops in the exif info both in LR and when I upload to flickr. I thought it might be me accidently moving the aperture (it's quite loose) but today I made sure. Despite having it in Aperture priority at 1.4, the exif reads 2.4. It has also displayed as 1.7 and 2.8 in the last few days. Thinking I may have it set in some kind of programme mode, I put it into Manual mode this evening. Despite using an aperture of 1.4 the iso remained at iso 200 and gave me and underexposure reading. Not sure if it's me or the camera..... any thoughts please? Further to this, I've read that the lens cannot tell the body what aperture it's using (yet) however, I'm still confused as to why the camera won't move the iso up to get a good exposure when it's in M mode and on auto iso?