EV or Exposure Compensation, what is it and when should I use it?
Exposure Compensation is a setting on your camera that can be used to quickly adjust for times when something is underexposed (too dark) or overexposed (too bright) causing you to lose details in your image. In simple terms if you have your camera adjusted to your desired exposure and you can see that a certain part of your image maybe overexposed (too bright) you can quickly use your EV setting to dial in “-” value to compensate and you do the opposite for underexposed areas of an image by dialing in a “+” value .
For example: If you are taking images of white birds on a sunny day they will normally be overexposed (too bright) even though your camera’s exposure is saying all is ok, so by simply setting your EV to say “-0.3” or more you will find that your white birds are now correctly exposed and therefore have more details in their wings etc.
So in plain english a “+” value on your EV setting makes the image brighter and a “-” value makes it darker
Another example might be if you are taking an image of someone standing in front of a window and the sunlight shining through the window is so bright that it turns the person into a dark silhouette. In this situation you could simply adjust your EV to compensate for this and get an exposure that is correct for your subject.
Let me give you an example of a dark background causing your camera to expose for your subject incorrectly:
Let’s say you are at a concert and you want to take a image of a band member on stage however they are in a spot light and the stage is almost total black, this will almost always throw off your camera’s’ metering system and result in the band member looking very pale, just use your EV to fix this and suddenly they look tanned and healthy again.
There is another situation that EV can provide assistance and that is when you are taking an image of something that is almost all white or all black. If the image you are taking is a close up of a black car your camera’s metering system will in some situations adjust for this and make it look like a bright grey (middle grey) again your EV will help you fix this. Conversely if you are taking an image of a snow field with a white rabbit in it then your camera will make it look grey instead of white, you guessed it EV to the rescue.
The above scenarios result because your camera’s exposure system thinks that it is seeing the full spectrum of tones in those images and therefore adjust it to middle grey which is halfway between black and white, so it thinks it is doing the right thing by balancing the scene however this is where it lets you down and the EV helps right it.