Sunday, February 15, 2009

How To Work A Digital SLR Camera

In my last blog post, I recommended the top cameras with the lowest costs for photography. Once you have the camera, you need to learn how to use it. This blog post will be all about how you work your camera so that you can get the best results in your photos.

The main things you need to know about SLR cameras in order to take a perfect picture is shutter speed, aperture, depth of field and your ISO setting.

Shutter speed can be defined as how long the shutter is opened. Shutter speed is represented by fractions. The bigger the denominator, the shorter the amount of time that the shutter is open. For example, 1/1000 represents a thousandth of a second and is therefore faster than a shutter speed of 1/60.
Example of a photograph taken using a slow shutter speed.

The longer the shutter is open the more light reaches the sensor. A very slow shutter speed can produce a blur in pictures. To get a sharp, clear picture, the rule of thumb is that you use a shutter speed of 1/60 of a second or larger.
Example of photograph using a fast shutter speed
Aperture, also known as F-Stop, refers to the amount of light that you are letting in through your lens. It is defined as the diameter that the shutter opens to to let the light in. If it is open wide it lets in more light then if it was barely opened. The aperture works similar to the way that your eye functions in letting light in and out. Also, Aperture settings are represented as decimal numbers. The numbers is where it gets confusing. Smaller numbers represent a larger aperture and vis-versa, larger numbers represent a smaller aperture. For example, an aperture of f/2.8 is larger than one of f/11. There is a large range of f-stops on most cameras, but different lenses have different ranges of f-stops. A cheaper lens might only open to an f-stop of 4.0 while a more expensive lens could reach as high as 1.6. Aperture and shutter speed directly relate to each other because as you change one of them, you must also change the other to counterbalance the first change. For example, if you have to increase the shutter speed so that you can capture a fast moving object then you must decrease the aperture so that your picture can still come out looking right.
Additionally, aperture directly affects the next aspect of taking a good photo; depth of field. Depth of field is the range of which your photo is in focus. A large depth of field puts more objects in focus, a greater distance from the photographer. A shallow depth of field puts things in focus that are closer and more prominent in the picture. For pictures that include a wide range of objects that you want to be in focus, a large depth of field should be used, while for close-ups a shallow depth of field is appropriate. Depth of Field can be manipulated using Aperture. A large aperture such as 2.8 lets in more light and is therefore used to create photos with a large depth of field. Similarly, a small aperture such as 11 lets in less light and is used for shallow pictures.Example of depth of field. Top photo has a shallow DOF and the lower photo has a wide DOF.
Lastly is ISO, which stands for International Organization for Standardization, is the standard
for measuring light sensitivity and how that affects the picture. The higher the ISO the more sensitive the sensor is to light. ISO is usually represented as larger numbers, such as 100 or 300.This chart shows the relationship between f-stop, located on the left, and shutter speed, on the right, with depth of field represented by the blue arrows.

When you are trying to take a good photograph, you have to consider all of the above aspects in order to obtain that perfect image. Each one directly affects the other. As we discussed, aperture and shutter speed correspond to each other, as well as ISO and aperture and depth of field. Therefore, understanding how your cameras works and how the functionality uses the things discussed is crucial to being a photographer.

Happy shooting!

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