About using Light in Photography,Tifa wrote this note & i found it useful & interesting,so i thought about publishing it here for all photography addicted:
Light is just like a coin for all photographers, bears two faces,, it could be very useful if he used it well and knew how to avoid its other face,, as for example any one can take a shot for a sunset over the Nile, but who can take care for the light composition? Or brightness or even contrast? They used to say "all places which are quite dark use ur flash, or else you may not use it.
That's all may be that was sufficient enough for analogue cameras but digital cameras I guess there are some additions were added beside this tip, things like:-
- EV "exposure value"
- ISO (sensitivity)
- shutter speed...
I guess there are other things but that's all what I knew related to light issue,
=now as for number 1 ( Exposure Value ) ,,, in case of large scenes area, it could be very bright, very dark or contain strong contrast, here comes the rule of the EV by adjusting its value we can avoid the bad results, in case of very bright scene, decreasing EV will b useful to decrease the amount of light entering to ur shot, and if the scene was very dark , of course we will increase the EV to light the taken shot a little-bit ,, it is something like controlling the bright and contrast degree in ordinary cameras or even in camera-mobiles.
For overexposed subjects (too light), decrease EV
For underexposed subjects (too dark), increase EV
EV has a scale ranged from +2 to -2 "that comes from my experience and knowledge may be there more or less scales" so either (+) increasing OR (-) decreasing the EV. Suggested Exposure Value settings*
- Bright sunlight coming over the back of you when taking a photo: -0.3 or -0.7 EV compensation
- For shots with strong light coming behind the subject (back lit): +0.7 or +1.0 EV
- Scene with bright sun: 0 to -2 EV
- Snow, beach or highly reflected water: -2/3 to -2 EV
- Close-up of white or yellow flower: -1/3 to -1 EV - Dimly lit night sky: 0 to +2 EV
- Land or seascape taken just prior to dusk: 0 EV to +2/3 - Very dark or black objects: + 2/3 to +1 1/3 Abbreviated from"http://www.digicamhelp.com/taking-photos/advanced-techniques/ev.php"
==number 2 ISO ,, it is the sensitivity of camera lens towards the light meaning, The higher the sensitivity, the less light is needed to make an exposure. Shooting at a lower ISO number requires more light than shooting at a higher ISO number.
Lower numbers result in images with the least visible noise, which is desirable.
The higher the number, the more noise "Noise is caused most often when taking photos with a digital camera using a high ISO number, usually over ISO 100. When noise is present in a photo, detail and clarity are reduced" .
The amount and degree of noise varies from camera to camera ISO settings AUTO ISO - digital camera automatically sets the ISO speed according the brightness of the scene, increasing or decreasing the sensitivity.
User has no control over which ISO number is used. ISO 50 - 80
- for taking photos in bright light; excellent for close-ups, landscape, and portraits.
Produces fine detail and image quality. ISO 100
- for extra sensitivity with little, if any, reduced image quality. ISO 200
- cloudy and overcast days. Acceptable image quality, with some visible noise. ISO 400 and above
- suitable for indoor photography whether or not a flash is used. Useful for "stop-action" and sports photographs. Most compact digital cameras produce high to very high image noise.
Changing ISO also changes the aperture and shutter speed. http://www.digicamhelp.com/camera-features/advanced-settings/iso.php number 3 shutter speed:- Shutter speed can be used creatively to create special effects in photos. the shutter speed control, also provides a new feature in camera that is called " PANNING " which is By tracking a moving subject, the subject stays in focus while the background is blurred. Panning requires practice. Make sure to lock focus on the subject. If your camera has a continuous mode or Panning Image Stabilization mode, use either or both. 
To freeze action, use a fast shutter speed. 
To capture the feeling of movement, use a slow shutter speed. Automatic panning could b found by using a slow synchronize flash option in some cameras, this option allows the blurring to the background and I tested this option many times it really helps if we don't have the manually controlling of the shutter speed, this option reduces the shutter speed So LIGHT could be a photographer friend or his enemy.
