The Depth of field: 3 factors

This is one of the most important thing for you about the composition and this topic need to know about lens aperture and speed shutter also. Depth of field determined as the region of proper available focus in your photographic image. This entire region of sharp focus is called the depth of field, or sometimes the depth of focus. As you ever know that in your picture will have the distance between your subject and background, you can set the depth of field for your image that how far for your sharp point.

3 factors that can control the depth of field:

1. Aperture
The aperture, I ever talked about aperture in Lens. Let�s me re-talk it again :) The aperture is the size of the lens opening that determines how much light reaches your camera�s imaging sensor. Unit of aperture = f/stops, if lower f/numbers, bigger openings and if higher f/numbers, smaller openings.
We can say that: Smaller aperture -> Greater the depth of field
As you can see here, the aperture of your lens directly influences how deep the depth of field is in any given picture: (speed shuter and focal lenght is same on both.

This below uses big aperture (small f/value) give the small depth of field

This below uses smaller aperture (high f/value) give the higher depth of field

2. Focal length (also ever talked in Lens)
It is just a measure of your lens�s ability to expand a scene. Depth of field is very important thing that come with the ability of lens. When shooting with a normal or wide-angle lens, you have a lot of depth of field. When shooting with a telephoto by zoom in, your depth of field reduce severely. When shooting with a macro/ close-up lens (magnifying a small object.) has very small depth of field as well. I can say in simple like the more you expand your subject, the less available depth of field you get. As you can see here, the focal length of your lens directly influences how deep the depth of field is in any given picture: (speed shuter and aperture is same on both)

First: use wider focal lenght -> High depth of field
Second: use narrower focal lenght -> Low depth of field
3. Subject distance
The distance from the subject determines how much depth of field you can get in your scene. If object that you want to take is very close to camera will have less depth of field in contrast if object is far from camera will have more depth of field. In sensible provisions, consider about the area of sharp focus for a macro shot; where the subject is only a few inches from the camera�is enormously narrow, and you require focusing very, very accurately. If you�re photographing object very far away�like a distant horizon�a vast region in front of and behind the image will be in sharp focus.

Besides from 3 factors , let�s think about how important of the depth of field from this situation. You are taking a picture with f/5.6. At a given distance from your subject, and at a given focal length, that f/stop will yield a certain depth of field. Nevertheless What Happens if you change the other two factors? (Walk toward it, or zoom in) The depth of field reduces. So you should know that depth of field is a really important aspect in the overall composition of your photographs. The use of depth of field can separate your subject by ensure it is only one thing that sharply and also you can increase depth of field to make the entire image can sharp as possible.