One Shot: Exposure
July 9, 2010
Think of shutter speed like baking a cake. The longer the time a cake is in the oven, the longer it is exposed to the heat. Similarly, the longer the shutter is released, the longer the picture is exposed to the light; however, be careful. Like how a cake can get undercooked or baked, a picture can be underexposed and overexposed so mind your time and cook that picture right!
The International Organization of Standards (ISO) is a numerical value that indicates the image sensor’s sensitivity to light. The higher the ISO the more sensitive the image sensor is to light. Thus, while high ISO is used in no flash zones and a events when there is little to no light (firework displays, churches, concerts, indoor sports events, etc.), low ISO is usually used when there is a great abundance of light (sunny days, well lit rooms, beaches, etc.). The higher ISO also permits the photographer to capture the same amount of light for faster speeds.
This control not only allows the photographer to control the brightness of an image but also the grain as well. While a picture taken with low ISO has a finer grain and smoother result, a picture taken with high ISO is very grainy. Generally, this is an unwanted effect known as the “noise”, turning up as multicolored speckles in a photo; however, in smaller format pictures, this may not pose as a great problem. Nonetheless to combat the effect, it is helpful to adjust the f stop and shutter speed.
The aperture is an opening through which light travels and is indicated with an f-number. The smaller the number (f/3.5) , the wider the opening and the bigger the number (f/22), the smaller the opening. This translates to the amount of light allowed to be exposed to your image. Just as with shutter speed, the greater amount of light the more overexposed the picture will be so be careful.
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