In many measurement situations, having to repeat the picture taking is expensive. Sometimes the object or scene you photographed no longer exists or has changed. Sometimes the site where pictures were taken is hard to reach and going back to redo the photography would be expensive. The photographs themselves are inexpensive and this is especially true of digital cameras.
For these reasons, it is a good idea to take many photographs of the object you are measuring. This way, if some of the photographs do not turn out, or if you wish to add some detail to the 3D model that was originally unplanned, you can use your existing photographs instead of going back to retake pictures.
Guideline 5: Take as many pictures of the object or site as you can, or as your budget will allow. As you start a project use perhaps three to six photographs. Add photographs later if you determine that some part of the scene or object is too difficult to measure with the current set of photographs.
Once the basic photographs have been taken, as outlined in Guidelines 1 through 4, extra photographs can be taken:
• closer up to get more detail,
• farther away to encompass more of the object or of its surrounds,
• in-between the planned Camera Stations,
• higher and lower than the planned Stations,
• with rolled (portrait vs landscape) positions if field calibration is a possibility, and
• with different exposure and aperture settings (if allowed by your camera).