Depth of field - what is it?

Today, photography is becoming morecommon. However, it can rightly be considered a kind of fine art. However, art is unusual, as it requires not only creative approach, imagination, but also technical knowledge.

Really highly artistic pictures can bedo only on a good SLR camera. In this case, it is not enough just to possess such a camera, it is necessary to understand it. And this is where theoretical knowledge will come in handy. It is necessary to know what is the depth of field, the aperture and the diaphragm number, the focal length. Only owning theory, you can use the camera fully.

Basic concepts of photography

For a proper understanding of what depth issharpness, you need to first determine the concepts of "focal length" and "diaphragm." We can say that the focal length is the main thing for removable lenses.

The focal length is the distance betweenplane of the matrix and the optical center of the lens. In this case, the viewing angle of a specific objective is determined by the ratio of the focal length to the diagonal of the matrix. Accordingly, the shorter the focal length, the wider the viewing angle.

To understand what a diaphragm number is,It is necessary to understand what the aperture of the lens is. It is essentially a hole through which light passes. In order for this hole to change, the diaphragm is made of several plates. When reducing these plates, the hole decreases, and light enters the lens less. When they dilute, respectively, light penetrates more.

A diaphragmatic number is an indicator thatinversely proportional to the diameter of the aperture in the diaphragm. It is denoted by the letter f. That is, when f has a small value, the aperture is wide open.

Now let's define what is the depth of fieldlens. This is a range of clear vision of objects that are in front of the subject and behind it. As it should be clear from the definition, much will depend on which object will be focused.

Depth of field depends on what?

Of course, it is very important for a photographer to know everythingdescribed characteristics of the camera, and also be able to control them. Depth of field can vary depending on several parameters. The main thing on which this indicator depends is the diaphragm number or the diameter of the diaphragm.

Dependence in this case directlyproportional. That is, the larger the diaphragm number, the stronger the depth of field. You can feel it yourself by taking pictures of the same object with different aperture. With a f / 22 diaphragm number, the depth of field will be greater than at f / 8.

Many may think that in this case it is betterto photograph at the maximum closed aperture, but this is not so. After all, it is not always necessary to get a clear picture to get a good photo. This is especially true in the case of portrait photography. Often, to get a successful portrait, it is necessary that the background is blurred. This is exactly what you can get by opening the wide diaphragm.

Or there are times when you need to focus on a particular part of the face. Then also shooting with a wide open aperture is used.

Also, the clarity of the image depends on the luminositythe objective, that is, the maximum amount of light that can pass through it. Often for studio shooting, high-speed lenses are used, which have the maximum throughput.

If you are going to take pictures on the streetwith good natural light, then you absolutely do not need to acquire such an objective. Since natural light is enough to get photos with a clear image of objects.