Theory of photography

Camera  : A camera functions in a very near manner of the eye . The lens corresponds to the crystalline, the diaphragm to the iris, the electronic sensor to the retina .

The big difference is the zoom that can vary the size of the image. That would correspond in the fact that the eye would have a variable length ( depth ) .

Focal: The focal length corresponds to the distance between the objective and the electronic sensor. More the focal is short more the objective transmits a wide image .

We call the focals not corresponding to the human eye  Wide Angle ( that farths the subject and minimise it ) and Telephoto ( that nears the subject and enlarge it ) .

Focus : The focus consists to adjust the distance between the lens and the sensor ( according to the distance of the photographed subject ) in order that picture is sharp .

Diaphragm : The diaphragm adjust the light that passes by lens . Aperture of diaphragm is determined by a number , more it is small more the diaphragm is opened .

More the diaphragm is closed ( great number ) more the clarity of picture and the depth of field increase .

Speed : More the speed to take a picture is rapid more the diaphragm has to be opened to determine the quantity of optimal light that reaches the sensor .

These two adjustments are always linked , it is necessary to choose if we prefer the speed or diaphragm’s aperture ( more it is closed best is the result in clarity ) .

White balance : The color of the light varies according to the source ( daylight , tungsten lamp , neon tube ) . The balance serves to obtain the real white for the lighting .

Depth of field : The depth of field indicates between what distance a nearest object and a farthest object on the photography are well defined ( sharp ) .

Zoom : The optical zoom and the numerical zoom have not the same result . The optical zoom vary the size of the image but also the relative appearance of elements

( according to the distance ) . The numerical zoom vary the size of picture but it remains the same , it is also less defined ( pixels of the picture are enlarged ) .

Zoom : The optical zoom in wide angle position decreases the size of objects , separates the different objects and increases the depth of field .

In position telephoto it increases the size of objects , brigs together the different objects and decreases the depth of field.