Sun 10-Jun-12 02:34 PM | edited Sun 10-Jun-12 02:38 PM by ZoneV
>Some cameras, including my D700, already have a virtual >horizon function that can help in setting the camera >horizontal or vertical. > >What is strange is that this data is not included in the exif >information of the picture.
But that data relies upon user feedback. You have to physically align the camera to the virtual horizon. It does not do it for you. I believe the purpose of the virtual horizon is actually not to give a reference to absolutely level the camera. Rather it is a guideline that you can reference when positioning your horizon. You need to determine the angular correction needed based on your perspective, and apply it yourself.
Due to landscape features, the actual horizon is seldom the same angle as the ground the tripod is placed upon. Further, perspective (due to lateral camera position variation) determines the actual angular correction needed for a level horizon to appear level in the photo. So the virtual horizon is simply a guide that uses the camera orientation sensor as a starting point...it's not meant to be used as an absolute reference to determine if the camera is level. It does not always work for this task. Yes, it would work if you had a perfectly flat environment and a head-on camera angle. But how often do we really have that setup?