Photography 1 (1)

Definition

1, Photography is the art, science and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor or chemically by means of a light sensitive material such as photographic film.

2, Photography has many uses for business, science, manufacturing(e.g. photolithography), art and recreational purposes.

Controls from the Cameras

1, Focus
The adjustment to place the sharpest focus where it is desired on the subject.

2, Aperture
Adjustment of the lens opening measured as F-number which controls the amount of light passing through the lens.
Aperture also has an effect on Depth of Field and diffraction.
The higher the F-number, the smaller the opening; the less light, the greater the Depth of Field, and the more the diffraction blur. The focal length divided by the the F-number gives the effective aperture diameter.

(Depth of Field)
Low F-number
        |
Big Aperture
        |
More Light
        |
Shallow DOF (Which is focused on the subject, the rest is blurry. Sharp Subject, Black Back Ground)
_____________________________________________________________________________

High F-number
        |
Small Aperture
        |
Less Light
        |
Great DOF (Which shows everything clear in the photo. All Sharp)

3, Shutter Speed
Adjustment of the speed of the shutter to control the amount of time during which the imaging medium is exposed to light for each exposure. Shutter Speed may be used to control the amount of light striking the image plane; 'faster' shutter speeds (that is, those of shorter duration) decrease both the amount of light and the amount of image blurring from motion of the subject and/or camera.
(Slow speed makes brighter, fast speed makes darker)


4, ISO Speed
Traditionally used to "tell the camera" the film speed of the selected film on film cameras, ISO speeds are employed on modern digital cameras as an indication of the system's gain from light to numerical output and to control the automatic exposure system.. The higher the ISO number, the greater the ISO sensitivity to light, whereas with a lower ISO number, the film is less sensitive to light. A correct ISO combination of  ISO
speed, aperture and shutter speed leads to an image that is neither too dark nor too light, hence it is 'correctly exposed', indicated by a centered meter.
eg;
-100
-200                   Less Sensitive (clearer)
-300
-400
-500                   More Sensitive (blurrier)
-600

*Always set ISO first before shooting