When taking pictures of a document or check or just about anything flat on the floor or ground or desktop while holding the camera in landscape orientation, as soon as I take the picture the phone reorients it to portrait.
I never use any other modes other than "photo", so I'm not selecting portrait. If I take the picture several times, sometimes I can get it to remain landscape. I don't have any problem when taking a landscape oriented picture while the subject is perpendicular to the ground so I'm pretty sure it has something to do with the phone's spacial positioning sensor (or whatever that is called).
Do I need to manually override something to stop this "mind of its own" functionality?
I agree that the pictures can be manually rotated, but why make an additional step necessary? The picture orientation should default to how you hold the phone.
