Digital aerial cameras are replacing traditional analogue film cameras for photogrammetric purposes in a fast manner. The change to digital cameras is driven by economic advantages – even if the large format digital aerial cameras are more expensive as analogue metric cameras, they do not need film, there is no loss of time and no cost for film development and digital images don’t have to be scanned. In addition the image quality of original digital images is better as scanned analogue photos and digital cameras are more light sensitive, extending the daily flight time. Also the accuracy of digital cameras usually is better, even if here some open points have to be discussed. For the use in production the relation between ground sampling distance and photo scale is important; here often a misunderstanding of the relation exist because it is more complex as just the mathematical relation.