What is the history of aerial photography

Taking photographs of the surface of the Earth from the air — has many important civil uses such as mapping and crop surveying, as well as its military applications which include spying and battlefield reconnaissance.

There are two basic techniques involved in aerial photography, called oblique and vertical. Oblique photography is the simpler — it just involves flying over the site in a small plane while a photographer on board takes pictures using a hand held camera through an open window, the line of sight being at an angle to the ground. Such pictures are used mainly for their pictorial value, or for illustrating various types of land forms.

Vertical photography is a much more exacting technique, and uses large custom-built cameras mounted in the floor of the aircraft. As the term suggests, the cameras look vertically downward.

What is the history of aerial photography photo

A typical camera has a high-quality lens of 150 mm focal length, carefully designed so as not to introduce distortions into the image. The camera uses a 250 ft (76 m) roll of film 9 in. (230 mm) wide, and has a suction back to pull the film flat while the pictures are being taken. Exposure times vary from 1/200 to 1/1000 sec, depending on light conditions and the movement of the image being photographed.

The heights used for aerial surveys vary with local conditions and requirements, but are usually well above 1300 ft (400 m). The rate at which photographs are taken varies with the image speed, since the. aim is to make each shot overlap the former by 60 per cent. In this way, stereoscopic views are taken. Picture taking rates vary from a few seconds to one taken every couple of minutes.