Traditional Culture Encyclopedia - Photography major - What is the introduction knowledge of photography?

What is the introduction knowledge of photography?

What are the necessary knowledge of photography? In order to help you fully understand the knowledge of photography, I have compiled the introduction knowledge of photography for you. Welcome to read!

Necessary knowledge of photography major

Monocular reflection observer system This is the most common camera observer at present. It uses the mirror behind the lens to reflect the picture captured by the lens, and then refracts it with a pentaprism, so that we can see the upright image from the viewer.

The perspective observation system has no so-called mirror and pentaprism. Light enters our eyes directly through the viewer, and then the imaging range of the negative will be different from that of the viewer, which is called parallax.

Binocular reflection framing system This camera has two lenses, the upper lens is used as framing, and the lower lens is actually shooting. This system will increase parallax because of the different positions of the upper and lower lenses.

Focus adjustment focus ring, through the viewer's preview, makes the image clearly imaged on the film. Manual focusing is to adjust the focus ring by hand to complete the focusing work, rather than relying on camera autofocus. Auto-focus is to adjust the focus ring by using the built-in motor drive without manual operation, but the auto-focus camera must cooperate with the auto-focus lens to play this function.

The camera of the most primitive photographic imaging principle is a black box with a small hole. The light reflected by the scene passes through the small hole and then hits the photosensitive film. Because the light is emitted, it will continue to diverge through the small hole. The light originally emitted by points forms a circle on the photosensitive film, and the image is composed of many circles instead of points, which is naturally not clear enough. So a lens was invented to replace the round hole. Monoconvex lens is the simplest lens, but it is only a little better than pinhole, and the imaging is not clear enough. If multiple lenses are combined to minimize the aberration of each lens, it is a compound lens commonly used by all cameras now.

Focal length As far as a single lens is concerned, the distance from the focal point to the center of the lens is the focal length; Generally speaking, the focal length of a compound lens is the distance from the focal point to the aperture position, but it is actually the distance from the focal point to the rear node of the lens. The rear node of the telescope head is far in front of the front lens and the wide-angle lens is behind the last lens, so it is different according to the lens design.

The function of focal length is directly proportional to the imaging size. The longer the focal length, the greater the imaging, and the shorter the focal length, the smaller the imaging.

The focal length of a lens is inversely proportional to the viewing angle. The longer the focal length, the smaller the scene angle, the shorter the focal length and the larger the scene angle.

The focal length is inversely proportional to the depth of field. The longer the focal length, the smaller the depth of field, the shorter the focal length and the greater the depth of field.

The length of focal length is inversely proportional to the strength of perspective. The longer the focal length, the weaker the perspective, and the shorter the focal length, the stronger the perspective. The length of the focal length is inversely proportional to the contrast. The longer the focal length, the smaller the contrast, and the shorter the focal length, the greater the contrast.

Focusing on a scene in depth of field photography will form a clear area before and after the scene. This blank area is called Quan Jingshen, or depth of field for short. Three basic factors that determine the depth of field:

Aperture-Aperture size is inversely proportional to depth of field. The larger the aperture, the smaller the depth of field.

The focal length is inversely proportional to the depth of field. The greater the focal length, the smaller the depth of field.

Object distance-The object distance is directly proportional to the depth of field, and the greater the object distance, the greater the depth of field.

Brightness The brightness of a lens is the amount of luminous flux. The greater the amount of light entering the aperture, the greater the brightness, and vice versa. Brightness is calculated by the multiple of aperture coefficient, which is one of the important factors to determine the exposure.

The viewing angle of a standard focal length lens is about 50 degrees, which is what a person can see with one eye without turning his head and eyes, so it is also called a standard lens. The larger the camera frame, the larger the focal length of the standard lens.

Wide-angle lens, named for its wide shooting angle, is suitable for shooting close-range and large-scale scenes, and can deliberately exaggerate the strong sense of distance in the foreground, that is, perspective.

A telephoto lens is suitable for shooting distant scenes, and a small depth of field often makes the subject with blurred background stand out. Because the telephoto lens is too bulky, there is a design of telescope head, which is to add a negative lens in front of the lens and move the main plane of the lens forward, so that a shorter lens can be used to obtain the effect of long focal length.

Another design of reflective telescope head super telescope head is to use mirrors to image. However, due to design reasons, the aperture cannot be installed, so the exposure can only be adjusted by the shutter.

The lens of an aperture camera has a device to control the amount of light transmission, which is called aperture. The aperture is large, and the light transmission is large; Turn it down, and the amount of light will be small. Small aperture and large depth of field, a clear sense of Ming Rui; Large aperture and small depth of field can make the subject stand out, showing a sense of blur before and after the subject.

The function of aperture is to control the penetration of light and adjust the depth of field. The intensity of light passing through the lens to the film is inversely proportional to the square of the aperture coefficient. The depth of field is the range of clear imaging before and after the lens is focused, which is related to the lens focal length, aperture and the distance of the subject. The shorter the focal length of the lens, the smaller the aperture, the greater the depth of field and the greater the clear range, and vice versa.