What is the working principle of SLR camera?

In this system, the unique design of the mirror and prism enables the photographer to directly observe the image passing through the lens from the viewfinder.

It can be seen from the structural diagram of a single-lens reflex camera that the light reaches the reflector through the lens and is reflected to the focusing screen above to form an image. Through the eyepiece and pentaprism, we can see the scenery outside in the observation window. ?

The light passes through the lens and is reflected by the reflector to the frosted viewfinder. Through the convex lens and reflected in the pentaprism, the final image appears in the viewfinder.

When the shutter is pressed, the mirror moves in the direction shown by the arrow, and the mirror is lifted, and the image is taken on CCD or CMOS, which is consistent with what is seen on the viewfinder screen.

Compared with paraxial cameras, SLR cameras have the advantage that what you see is what you get, and the imaging angle in the viewfinder is the same as the final film.

However, compared with paraxial camera, the back focus of SLR camera lens should be able to image at the focal plane of reflector and photosensitive element at the same time, and false focus must be generated before imaging at the focal plane, which makes the structure of SLR camera optical lens more complicated and larger, and the imaging effect is not as direct and transparent as paraxial camera. At the same time, the volume of the "reflector" should be large.

Extended data:

Advantages:

1. Excellent imaging quality is the first reason why many consumers favor DSLR.

Because the photoreceptor area of DSLR is much larger than that of consumer cameras, and the pixels per inch are relatively greatly reduced, the performance of DSLR far exceeds that of consumer cameras in terms of latitude, resolution and high sensitivity.

The size of the photoreceptor is also the last factor that affects the sales of consumer cameras. Manufacturers often use other indicators such as high pixels to distract users.

In fact, the size of the photoreceptor is far more important than the number of pixels. The maximum size of the photoreceptor of consumer cameras is only11.7 inches, while the photoreceptor area of SLR is mostly APS-C (23.7mm× 15.6mm) to full size (36mm×24mm), which is the same as that of 135 negative.

2. The shutter of 2.DSLR is a pure mechanical shutter or an electronically controlled mechanical shutter. The shutter has a very short time lag, and it can be imaged after pressing the shutter, which is a sharp weapon for capturing pictures.

The start-up speed of DSLR is only a few hundred milliseconds, and the continuous shooting speed is also very fast. Consumer cameras, on the other hand, are pure electronic shutters, which has a serious shutter lag problem. This weakness can be called the weakness of consumer cameras, so you can shoot still life, but it is not suitable for capturing moving objects-the image you get is often not the action when you press the shutter.

3. The framing of the SLR camera is through the lens, which looks very bright, and the picture the user sees is the picture he will take. At the same time, the transparent light makes it easier to observe the focusing effect when focusing.

Consumer cameras take pictures through photoreceptors and LCD, so there will be some errors in the observation of brightness and color, which is not easy to detect, and it is even more difficult to see the picture clearly in the dark.

Even if there is an optical viewfinder on a consumer camera, its optical path does not pass through the lens, so there is parallax.

The lens of 4.4. The DSLR can be changed according to the shooting theme. The lens of consumer cameras cannot be replaced, and the lens quality is much worse than that of DSLR.

5.DSLR has many manual functions.

DSLR can easily zoom manually and set shooting parameters manually. , and you can take some special shots (such as shooting fireworks with door B).

But many consumer cameras are automatic. Most cameras don't have a manual zoom ring, so they have to zoom automatically by a motor. Because the speed of zooming is slow, many shooting opportunities will be lost. Many people think that automation is better than manual operation, which is really a misunderstanding. Cameras with automatic function but no manual function are often low-end cameras, because the accuracy and speed of automation are far less than that of manual operation.

Reference: Baidu Encyclopedia-Single lens reflex camera