We can control the depth of this area by using different-sized apertures. A small aperture produces smaller circles of lights (called circles of confusion) so that the area that appears sharp to us is larger than when a wider aperture is used. Here we must remember that smaller apertures have larger numbers. Thus f/16 represents a small hole than f/5.6.

A simple exercise will soon demonstrate this principal to you. If you have a depth-of-field preview button on your camera, set the aperture on it widest setting and focus on something reasonably close ( 2 meters or so) using a standard lens. Looking through the viewfinder you will see the amount of focused image available at the maximum aperture of your lens. Now close the lens aperture down to f/8 and use the depth-of-field preview to check the difference. Whatever is in the background of your picture might not be entirely sharp, but objects should be a lot more recognizable then they were before. Now close down to f/16 and check the difference again. By opening and closing the aperture with the depth-of-field activated, you will be able to see immediately what difference the aperture makes to the amount of the scene you can render sharply.

Click to enlarge

There is a little more to depth of field than the aperture, however. The two other elements you need to think about are the focal length of your lens and the distance of your subject is from the camera. Tn basic terms, the longer the focal length of the lens you are using, the shorter your depth of field; and the closer your subject, the shorter your depth of field. Conversely, for the maximum depth of field you should use a shot focal length lens (i.e. a wide angle) and focus on a subject that is a long way away.

You can use depth of field either to show the whole scene in front of you in focus or to highlights just a single object as the main subject by rendering it the only sharp point of the picture. It is a powerful tool and you need to think about every time you look through the lens.

p/s: See you all next post

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An aperture is more than just a hole in the lens which lets the light in. The size of that aperture governs the appearance of your final result just as much as fast or slow shutter speed portrays the movement of your subject. The aperture controls not only the amount of light entering the lens, but also how much of the depth within your picture is rendered sharp and in focus.

When we look at a photograph, what we are seeing is lots of tiny circles of light which build up the image of the subject. The bigger circles, to the human eye, create an out-of-focus subject, while the small ones create a subject that looks sharp. The point on to which the lens has been focused produces the smallest circles, while a certain amount of information in front and behind that point is constructed of circles small enough still to appear sharp to our eyes. This area is called the depth of field.

p/s: Camera Basics – Controlling Aperture Part 2

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Imagine looking through a window. The window has a set of curtains which you are holding in your hands. Those curtains are closed. You hear a car outside and you want to see it. If you open and close the curtains very, very quickly you might not be able to tell whether the car is moving or not. You will see there is a car there, but the length of time you were able to spend looking at the car might not have been long enough for you to determine whether it was parked or in motion. If you had kept the curtains open for a little longer, you would have been able to see quite clearly whether the car was moving. This how shutter speeds work. Shutter speeds determine how low you let the censor or film see the subject. If the film or censor does not get a good long look, how can it know the subject is on the move? If you let it have a long look it will see the subject is moving and will show it in final image.

Thus we can see how the shutter speed basically determines whether your subjects looks as if it is moving or not. You might want to freeze your subject’s movement with a fast shutter speed or you might want to show it is moving by using a slower shutter speed. However, do not be trapped into thinking ‘fast-moving subject, therefore select fast shutter speed’ when showing that the subject is moving might be far more interesting.

Next: Camera Basics – Controlling Aperture Part 1

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The firs step in taking control of your photography is to learn how the aperture and shutter speed relate to one another, and to recognize how they effect the look of the final image. If you have been accustomed to using a compact camera you will find that shutter speed and aperture control give you a whole range of new choices and freedom of creativity.

Exposure is the process of allowing light to pass through a certain-size hole for a certain length of time. The size of the hole is what we call the aperture, and the time the light is allowed to pass is call the shutter speed. What is important is that the right quantity of light reaches the censor. For a particular scene of certain brightness there will be a variety of apertures and shutter speeds you can use.

When you halve the length of time you allow the shutter to remain open – for example, from 1/250 second down to 1/500 second – you need to double the size of the aperture – for example, from f/16 to f/11. Every time you move a stop either way on the shutter speed or the aperture dial, you either halve or double the amount of light admitted. If your camera gives you a meter reading of f/8 and 1/250 second, f/4 and 1/500 second or, in the other direction, f/11 and 1/60 second. This is known as the reciprocity law. But shutter speeds and apertures have a far greater impact on your photography than merely getting light on to the film or censor.

Next: Camera Basics – Controlling Shutter Speed

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Imagine you are shooting a landscape picture where bang in the center of your frame is a bright, white building. If set to automatic exposure, your camera will assume this is the most important area of your picture, and if set to auto focus, it will also assume this the area you want to focus on. However, in the foreground of you frame is a large, beautiful and extremely rare black rose, and this is the part of the composition you would prefer to draw attention to. If you went ahead and believed what the camera was telling you, both the exposure and the focusing would be wrong for what you were trying to archive.

This is why it is important to take control of your camera. Having a good eye for a picture is a very good start, but you will have to master a certain amount of technical detail in order to archive good pictures every time.

Next: Camera Basics – Aperture & Shutter Speed

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