What is the imaging principle of a DSLR camera?

1. Framing: The light (image) is projected onto the reflector placed at 45 degrees through the lens, refracted to the Wuling lens on the top of the camera, and then projected to the viewfinder eyepiece through the two refractions of the Wuling lens. The photographer sees an upright image through the eyepiece that looks like the real thing.

2. Shooting: The photographer presses the shutter, the reflector turns up, opens the light path of the lens to the film (or CCD or CMOS), and the reflector blocks the light path leading to the Wuling lens at the same time to prevent the stray light from entering the camera through the eyepiece in reverse and affecting the imaging. At this time, the aperture is retracted to the preset value, the shutter is opened, the image recording medium records the image, the shutter is closed, the aperture is returned to the maximum, and the mirror is returned to prepare for the next framing and shooting.

In SLR cameras, film SLR and DSLR have the same principle, but the medium of recording images is different. Of course, because the recording medium is different, its structure is also quite different.

The above only describes the light trajectory of the SLR camera, and there are some such as the action of the aperture, the control of the shutter, the control of the flash, the combination of metering and **, ranging and focusing, etc., which cannot be described here.

There are reflex cameras. Just like the domestic seagull 4a, 4b, etc., it used to be commonly known as the "square mirror box".

The reflex camera uses two lenses, which are placed up and down, generally the upper lens is framed and the lower lens is shot. Since there is no Wuling mirror, the image seen by the photographer is upside down, left and right, and the operation during framing will be inconvenient.

In addition, since the reflex camera uses two lenses to frame and shoot separately, there is a "parallax" problem, that is, the range of the image seen by the photographer is not the range recorded in the shooting. The SLR camera solves this problem more thoroughly, because it completes framing and shooting through one lens, and basically achieves "what you see is what you get", which is also one of the reasons for the rapid development of SLR.

There is also a camera called a "rangefinder", which is viewed through a special viewfinder window on the body, and the lens records the image. Because it is not framed and filmed through a single lens, there is also a problem of "parallax".

Digital Single Lens Reflex (DSLR) cameras, abbreviated as DSLRs. In this system, the unique design of the mirrors and prisms allows the photographer to observe the image passing through the lens directly from the viewfinder. As you can see from the construction of a single-lens reflex camera, the light passing through the lens reaches the mirror, is refracted to the upper focusing screen and forms an image, and through the eyepiece and pentaprism, we can see the outside through the viewing window.

The light passes through the lens (1) and is reflected by the reflector (2) into the frosted viewfinder (5). Through a convex lens (6) and reflected in a pentaprism (7), the final image appears in the frame (8). When the shutter is pressed, the mirror moves in the direction indicated by the arrow, the mirror (2) is picked up, and the image is taken on the CCD (4), which is the same as seen on the viewfinder screen.

The imaging principle of the camera is as follows:

The optical imaging system of the camera is designed according to the principle of geometric optics, using the linear propagation nature of light and the refraction and reflection law of light, using photons as the carrier, the amount of light information of the photographed object at a certain moment is transmitted to the photosensitive material through the photographic lens in an energetic way, and finally becomes a visible image.

When the camera takes pictures, it must control the appropriate amount, that is, the appropriate amount of photons that reach the photosensitive material.

Because there is a limited range of photons received by silver salt photosensitive materials, too few photons cannot form a latent nucleus, and too much overexposure is formed, and the image cannot be distinguished. Use the aperture to change the clear aperture of the lens, control the amount of photons per unit time to reach the photosensitive material, and change the shutter opening and closing time to control the length of time.

Cameras are classified as follows:

1. According to the film and format size used by the camera.

It can be divided into 35mm cameras (commonly known as 135 cameras, 110 cameras, 126 cameras, medium format cameras, large photo cameras, APS cameras, micro cameras, etc.). The 135 camera uses 35mm film, and the standard format it shoots is 24mm, x, 36mm, and generally 36 or 24 shots per film.

2. According to the appearance and structure of the camera.

It can be divided into heads-up finder cameras (viewfinder) and single-lens reflex cameras, and single-lens reflex cameras. There are also foldable cameras, dual-lens reflex cameras, head-up rangefinder cameras (RangFinder), transit, landline, and more.

3. According to the functional and technical characteristics of the camera.

It can be divided into autofocus camera, electric metering manual camera, electric metering automatic camera luggage, etc. In addition, there are shutter priority cameras, aperture delay priority cameras, program-controlled cameras, dual-priority cameras, motorized film (automatic winding, rewinding) cameras, autofocus (AF) cameras, date back cameras, and built-in flash cameras. <>