By: Grace Wanja
There are a number of aspects digital photographers need to learn something that prompted me to write a series of articles to help them know how to move from Auto mode and manually set exposure of the shots they make. I concentrated mainly on 3 elements of the exposure triangle i.e. Aperture, Shutter Speed and ISO. Below you will learn details about Aperture.
Before you get to learn more about it, it is important to note that mastering aperture gives you a great chance to grasp creative control over the camera. This is where the magic of photography takes place, and you will soon discover the difference between multi-dimensional and dimensional shots.
Aperture simply put can be described as opening in the lens. When the shutter release button on the camera is hit, the camera image sensor normally catches a glimpse of the scene you want to capture after a hole opens up. The size of this hole is normally impacted by the aperture set. This implies that if there is a large hole, more light will get in and vice versa.
Aperture is measured using f-stops. In Digital Photography School, this is normally referred to as f/number. For instance: f/2.8, f/5.6, f/22 and so on. When you move from one f-stop to the other it halves or doubles the size of the opening in the lens affecting the amount of light that passes through. Note that when the shutter speed changes from one step to the other, it will half or double the amount of light that manages to pass through. This implies that if you increase one and also decrease the other, the same amount of light will be passed in. this comes in handy thus you should not forget.
Large apertures that pass in a lot of light normally create a lot of confusion among new photographers because they are given small f/stop numbers and smaller apertures are normally given large f/stop numbers despite the fact that they let in less light. In essence, f/2.8 is generally a larger aperture than the f/22. It may sound wrong when you first hear it but you will get used to it once you get a hang of it.
Depth and Aperture and Field
When you change the aperture of the shots you are taking, there are usually a number of results that you should know about especially if you would like to change settings where the most noticeable will actually be the depth of field that the shot will have.
DOF (Depth of Field) is the amount of shot that is in focus. A large DOF means that most of the image will be in focus whether it is far away from the camera or close by. Shallow or small DOF means that only a section of the image is going to be in focus thus the rest will be a bit fuzzy. Aperture usually has a huge impact on the DOF. Large aperture normally decreases the depth of field while the larger numbers or small Aperture gives a larger DOF. To avoid confusion, remember that large numbers imply large DOF while small numbers are equal to small DOF.
For instance you can take a picture of a flower and have different results based on the aperture that has been used. You can use aperture of f/22 and take the other with aperture of f/2.8. You will notice quite a huge difference because the one where f/22 is used might show more detail of the flower including the bud. Here you will also be able to make out the elements in the background without any problem. On the other hand, when you take the shot using f/2.8, the background is normally thrown out of focus and you can see that the picture was taken when the photographer was holding the camera slightly further from the subject when the shot was taken.
Image source: http://forums.srellim.org/showthread.php?t=5940http://forums.srellim.org/showthread.php?t=5940
The best way that you will get to fully understand aperture is by taking out your camera and experimenting with it. This is because reading about it is not enough and it may even lead to further confusion thus you need to see the reality on the ground. For this you will need to take your camera and look for the ideal spot outside where you can get items that are close and far away from you. This will allow you to take different pictures where you can compare the results when you are done to know how aperture really affects your shots. Use different aperture settings to take some shots going from the smallest to the largest. This will allow you to see the impact that this comes this and you will understand why it is important to have full control of aperture.
There are some styles of photography that normally require large DOF as well as small Aperture. For instance, if you are interested in landscape photography, you will view small aperture settings or large numbers selected by most photographers. This way the foreground to the horizon remains relatively in focus.
On the other hand if you are engaged in portrait photography, it would be advisable that you the image you are dealing with in perfect focus and get a nice blurry background so that that you can also make certain that the subject remains the main focal point and all the other elements do not come close to distracting it. In this case, you would be better off working with a small number (large aperture) so as to ensure you achieve shallow DOF. Here is an example:
Image source: http://www.macworld.com/article/1150150/depthoffield.html
Macro photographers tend to lean more on the use of larger aperture which helps to ensure that the elements on the main subject which are being focused on are captured in the attention of the image viewer while the rest of the shot is thrown out of focus completely.
I do hope that you found this piece educative and useful. Be on the lookout for the other part of the series that will handle an introduction to Shutter Speed and introduction to ISO.