photo sharing and upload picture albums photo forums search pictures popular photos photography help login
Commenting on this page requires full PBase membership.
Please login or register.
Terry Bowker | profile | all galleries >> Camera Obscura Chicago tree view | thumbnails | slideshow

B&W / Color Awards | Burning Man | C A M B O D I A | Chicago | CHINA, Beijing | CHINA, Hong Kong | CHINA, Shanghai | CHINA, XI'AN | Delhi India | Agra India | Mumbai India | Istanbul | Marrakech | Metropolitan New York | Europe | JAPAN | Venice Italy Carnival | Vietnam | USA WEST COAST | Maine | Nearly B&W | Flight | Flora | Fauna | Odds & Ends | Photo Manipulation | Camera Obscura Chicago | Eve | Mom's Birthday | In Box

Camera Obscura Chicago

The camera obscura (Lat. dark chamber) was an optical device used in drawing, and one of the ancestral threads leading to the invention of photography. In English, today's photographic devices are still known as "cameras".
The principle of the camera obscura can be demonstrated with a rudimentary type, just a box (which may be room-size) with a hole in one side, (see pinhole camera for construction details). Light from only one part of a scene will pass through the hole and strike a specific part of the back wall. The projection is made on paper on which an artist can then copy the image. The advantage of this technique is that the perspective is accurate, thus greatly increasing the realism of the image (correct perspective in drawing can also be achieved by looking through a wire mesh and copying the view onto a canvas with a corresponding grid on it).
With this simple do-it-yourself apparatus, the image is always upside-down. By using mirrors, as in the 18th century overhead version illustrated in the Discovery and Origins section, it is also possible to project an up-side-up image. Another more portable type, is a box with an angled mirror projecting onto tracing paper placed on the glass top, the image upright as viewed from the back.
As a pinhole is made smaller, the image gets sharper, but the light-sensitivity decreases. With too small a pinhole the sharpness again becomes worse due to diffraction. Practical camerae obscurae use a lens rather than a pinhole because it allows a larger aperture, giving a usable brightness while maintaining focus.

All images copyright ©Terry Bowker, and may not be reproduced, including copying, transmitting, downloading, saving as a digital file, or linking to, without the written permission of the photographer.
http://terrybowker.smugmug.com/
Camera Obscura Bedroom
Camera Obscura Bedroom
Camera Obscura Bedroom
Camera Obscura Bedroom
Camera Obscura Bedroom
Camera Obscura Bedroom
Camera Obscura Bedroom
Camera Obscura Bedroom
Camera Obscura Sears Tower
Camera Obscura Sears Tower
Camera Obscura Sears Tower
Camera Obscura Sears Tower
Camera Obscura
Camera Obscura
Camera Obscura (Chicago)
Camera Obscura (Chicago)