Today, i thought i will explain photographic terms like Shutter speed and Aperture. If you get a grasp on these terms and how they work, you will make good photos quickly without much fiddling around with settings and stuff. I will try and keep it short and simple. There's lots of detailed info on the internet.
Shutter Speed and Aperture:
As you've read (if you have!) on my earlier post about "How a Digital Camera makes a Picture?", when you take a picture, the shutter opens and closes for a small amount of time, during which the sensor is exposed to light. This duration, for which the shutter remains open is called Shutter Speed. It is usually expressed as a fraction of a second.
Example: This picture of water flowing out of a faucet was shot at a Shutter speed of 1/60 seconds.
What this means is the shutter remained open for one sixtieth of a second, or simply written 1/60. In general, 1/60 usually freezes slow moving subjects if they are well lit. Faster subjects like people and animals running, etc can be frozen with shutter speeds of 1/200 or faster.
The shutter speed alone, however will not decide how the picture looks. It also depends on the Aperture.
The Aperture is simply the size of the lens iris. It is the size of the opening, that allows light to enter. The bigger the opening, more light can enter at given shutter speed. It is just like how our eye pupils dilate or contract when they are exposed to bright or dark surroundings. The aperture also decides the Depth of Field (DOF) and i will discuss this in the next post.
Shutter speed and Aperture work together to create a well exposed image. Aperture is expressed as a fraction of the focal length. It is also denoted as "f-number" or "f-stop".
Lets consider another example:
This shot was made at a shutter speed of 1/200 and aperture of f/7.1 . This means, to get a well exposed image, the shutter had to remain open for 1/200 of a second, and the iris had to open to a size equal to 1/7.1 of the focal length. Now, the focal length at which this image was made is 31mm. Thus, the aperture is 31/7.1= approx 4.4 mm.
OK, now the fun part is that all the digital cameras and most modern film cameras calculate the shutter speed and aperture automatically. So you get perfectly exposed pictures always. But if you want to get creative, you will want to adjust these by yourself. That's where Manual mode come into play! More on shooting modes next time!
As a summary, remember, the most important factor in getting a good photo is the light. So, the shutter speed is used to control the time for which an exposure is made. Fast moving subjects need faster shutter speeds to freeze them, otherwise they will look like a blurry ghost like object. (This might be used sometimes to accentuate speed). The aperture is the size of the opening of the iris. It determines how much volume of light enters during the shutter duration. It might be a little confusing, but its simple physics. Just remember that the two terms are important and are linked closely.
Hope it helped. Next post will be about Depth Of Field and ISO.
Thanks!
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