Originally Posted by
DaveReidUK
Try it next time you're at the airport - take a picture of a departing airliner with your camera upside-down, and see if the passengers notice any difference.
My views on photographic composition may be a bit old fashioned. I prefer the sky at the top, ground at the bottom, and features that are vertical to appear vertical in the image.
Had I taken the photo with the camera upside down, and there are good reasons to sometimes do that with an SLR, I would simply have rotated the image when I got home. The passengers would also have been unaware of this second inversion.