What's EV and when to use it.

Its complicated maths that denotes multiple Aperture and Shutter Speed settings for an exposure (taking a photograph).

Exposure Values (EV)	digital-photography-school.com
EV +2, lighter photo.	EV +0, normal photo.	EV -2, darker photo.

When to use:

• If your camera insist on lighter/darker photos and you disagree.
• You need more shutter speed (increase aperture = more light, reduce EV = darker photo, allowing higher shutter speed).
• When your subject is darker than background, increase EV, and vice versa.
  
  

  	digital-photography-school.com
  Subject lighter than background, EV +0	EV set to EV +1.3

  
  
• With a tripod, take the same photo with different EV and then stitch them together in PhotoShop to create a High Dynamic Range photograph.

 

References:

• http://en.wikipedia.org/wiki/Exposure_value
• http://digital-photography-school.com/ev-compensation-explained