In my last blog post, I introduced Auto Exposure Bracketing (AEB) and Exposure Compensation.
Here I would like to explain more about using Exposure Compensation .
The photos below were taken using AEB in Aperture Priority Mode i.e. the camera determines the shutter speed. (Note: I targeted the train station using spot metering)
A total of five photos each one exposure value (EV) apart were taken. It’s important to note the change in the speed for each of the EV changes and how the histogram shifts right or left with the change in EV.
As you decrease the exposure by 1 EV the photo gets darker and the speed increases i.e. doubles 1/250 to 1/500. If you increase the exposure by 1 EV the photo gets brighter and the speed decreases 1/250 to 1/125. For a decrease by 2 EV the speed doubles again from 1/500 to 1/1000 and if you increase by 2 EV the speed changes from 1/125 to 1/60.
Normal (1/250 sec)
-1 Exposure Value (1/500 sec)
+ 1 Exposure Value (1/125 sec)
+ 2 Exposure Value (1/60 sec)
-2 Exposure Value (1/1000 sec)
Digital cameras allow you to set EV Step to either 1/3, 1/2 or 1. (See your camera’s manual on how to set the EV step for your particular camera.)
In the photos below I adjusted the camera by +1/3 EV each time. As you can see the difference in each photo is very slight. Therefore, I believe an EV step of 1/2 would have been sufficient as there is only a very small change in each of the exposures.
Remember the goal is to get as close to ideal exposure as possible. While you have the ability to make corrections to exposure, along with contrast, highlight and shadow detail using photo processing software, it’s important to get the exposure correct in the original photo. When making changes to exposure on your computer/tablet there is the potential to add noise that will degrade the quality of the image. Had I chosen a different metering mode the image results would/could have been slightly different, but that’s a topic for a future blog post on metering modes.
Below you will find two links that provide additional details on exposure compensation: http://www.picturecorrect.com/tips/exposure-compensation/
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