How to use exposure correction
Are your photos sometimes too dark or too bright, even though you have used automatic exposure? Then you’re not alone. Faulty exposure can initially exasperate many passionate photographers. It’s caused by the camera’s automatic mode determining aperture and shutter speed based on a standard value, which often doesn’t match the way the photographer has perceived the scene.
Even professional SLR cameras equipped with the latest image processors cannot calculate the exposure as accurately as the photographer sees the image.
What should you do in the event of faulty exposure?
Fortunately, almost all camera have a way of manually correcting exposure, usually shown with a +/– symbol. The relevant key or key combination on both point-and-shoot cameras and professional SLRs is generally quite easily accessible with your thumb or index finger – an indication of how often even experienced photographers have to use this function.
How do I achieve correct exposure?
In principle, it’s very easy: If the image is too dark, use the +/– function to set a positive value. If it’s too bright, select a negative value. A correction value of +2/3 EV or -2/3 EV is a good starting point.
At this point, it’s worth making a brief digression into the theoretical side of things: The abbreviation EV stands for Exposure Value. Depending on the format, each unit on the exposure-value scale denotes a doubling or halving of the amount of light. The aperture and shutter-speed sequence operates in the same way. If, for example, you open the aperture from f/8 to f/5.6, this equals a doubling. The same applies if you lengthen the shutter speed from 1/125 to 1/60 seconds. And what about the values in between, e.g. f/6.7 or 1/100 sec? They denote half or one-third exposure value levels.
Initially only correct the exposure by around two thirds of a stop (plus or minus). This minimises the risk of excessive under or overexposure. In many cases, this correction will be enough to achieve the desired exposure effect. Check the result on the display and increase the correction if the image still looks too dark or bright.
You should generally be careful with correction values of more than one exposure value, as this can cause full shadows or blown-out lights. After taking the shot, check the bar chart to make sure the definition is still there in the important areas.
Equipped with this knowledge, you’re now able to accurately correct exposure at any time, and not only in extreme lighting. You’ll be amazed at in how many situations you’ll be able to use the correction function to give your photographs a creative, personal touch.