What's so good about SLR cameras? What kind of person is it suitable for?

DSLR digital cameras refer to single-lens reflex digital cameras, that is, digital digital, single-lens, lens reflex and reflex. At present, the common SLR digital camera brands on the market are Nikon, Canon, Pentax, Fuji and so on. Working principle:

In the working system of SLR digital camera, after the light reaches the reflector through the lens, it is refracted to the focusing screen above to form an image. Through the eyepiece and pentaprism, we can see the scenery outside in the observation window. In contrast, ordinary digital cameras can only see the captured images through the LCD screen or electronic viewfinder (EVF). Obviously, the directly seen image is more conducive to shooting than the processed image.

When shooting in DSLR, press the shutter button, the reflector will pop up, and the shutter curtain in front of the photosensitive element (CCD or CMOS) will be opened at the same time, and the light passing through the lens will be projected onto the photosensitive original, and then the rear reflector will be restored immediately, and the image can be seen in the viewfinder. This structure of the single-lens reflex camera ensures that it is shot through the lens, so that the image seen in the viewfinder is always consistent with the image on the film, and its framing range is basically consistent with the actual shooting range, which is very conducive to intuitive framing and composition. Main features:

A major feature of SLR digital cameras is that they can change lenses of different specifications, which is an inherent advantage of SLR cameras and incomparable to ordinary digital cameras.

In addition, the SLR digital camera is now positioned in the high-end products of digital cameras, so the area of the photosensitive element (CCD or CMOS) related to the photographic quality of digital cameras is much larger than that of ordinary digital cameras, which makes the photosensitive area of each pixel of SLR digital cameras much larger than that of ordinary digital cameras, so each pixel can show more detailed brightness and color range, which makes the photographic quality of SLR digital cameras significantly higher than that of ordinary digital cameras.

A telephoto digital camera refers to a model with a large optical zoom factor. The larger the optical zoom factor, the farther the scene is photographed. Representative models include Minolta Z series, Panasonic FX series, Fuji S series and Kodak DX series. In some digital cameras, the longer the lens, the larger the moving space of the internal lens and the photoreceptor, so the larger the zoom factor.

In order to better understand the concept of telephoto, please read the meaning of optical zoom and digital zoom of digital camera first.

Main features:

The main feature of telephoto digital camera is actually similar to the principle of telescope, which changes the focal length through the movement of the lens inside the lens. The benefits of telephoto come into play when we shoot distant scenery or photographers don't want to be disturbed. In addition, the longer the focal length, the shallower the depth of field, which is the same as the larger the aperture. The advantage of shallow depth of field is to highlight the subject and blur the background. I believe that many fans pursue shallow depth of field effect when taking photos, making the photos more professional. In some digital cameras, the longer the lens, the larger the moving space of the internal lens and the photoreceptor, so the larger the zoom factor.

At present, the optical zoom magnification of digital cameras is mostly between 3 times and 12 times, and objects beyond 10 meter can be zoomed to 5-3 meters. There are also some digital cameras whose optical zoom effect is 10 times. The optical zoom factor of home camcorder is 10 -22 times, and it can clearly shoot things 70 meters away. Using a magnifying glass can increase the optical zoom factor of the camera. If the optical zoom factor is not enough, we can add a zoom lens in front of the lens. The calculation method is as follows: A 2-fold zoom lens is set on a 4-fold optical zoom digital camera, and then the optical zoom multiple of this digital camera will be changed from the original 1, 2,3,4 times to 2,4,6 times and 8 times, that is, it is obtained by multiplying the zoom lens multiple and the optical zoom multiple.

The larger the zoom range, the better?

For the overall quality of the lens, in fact, the larger the zoom range, the worse the lens quality. Lens distortion and dispersion are two common problems in 10x ultra zoom lens. Purple border is very serious. Super zoom lens is prone to barrel deformation at the wide-angle end and pillow deformation at the telephoto end. Although lens deformation is inevitable, a good lens will control the deformation within a reasonable range.

Theoretically, the larger the zoom factor, the easier it is for the lens to deform. Of course, many manufacturers have also made a lot of efforts to this end. For example, manufacturers usually add aspherical lenses to lenses to prevent this deformation. For dispersion, manufacturers usually use anti-dispersion lenses to avoid it, such as Nikon's ED lenses. With the development of optical technology, the current 10 zoom lens should actually meet the needs of our daily shooting in terms of optical performance.

supporting facilities

For these super-large zoom digital cameras with 10 times optical zoom lens, some overall defects will have a fatal impact on the final shooting quality and user's use.

1, the telephoto end focuses slowly. As we all know, the autofocus technology of consumer digital cameras is not very advanced, and it is not ideal in terms of speed. This is why many people use consumer digital cameras for a while and then switch to digital DSLR. For these 10 zoom machines, the autofocus at the telephoto end will be tested even more. Judging from these machines currently on the market, many machines do have defects in this respect. Mainly manifested in the focus is uncertain, or unable to focus, which is especially obvious in dark places.

2. Shake when holding. Most friends who are familiar with photography know the concept of safe shutter speed. The safety shutter speed is actually the reciprocal of the focal length. The so-called safety means that if the shutter speed you use is higher than the safe shutter speed, the photos you take will not be blurred because of uncontrolled shaking of your hands. On the contrary, if it is lower than this speed, it will be more dangerous. Because the focal length of a digital camera with 10 times optical zoom is very large, we are required to ensure a high shutter speed when shooting. Otherwise, it is easier to lose precious wonderful pictures.

3. Image quality. We have actually talked about this problem above. As far as the ultra-large zoom digital camera that has just been listed at present is concerned, its image quality is not strictly a good category, especially the telephoto end.

4. Weight and volume. With more and more lenses used in digital camera lenses with zoom 10 times, the aperture and volume of the lens will also become larger, resulting in a corresponding increase in the volume and weight of the camera. Although there are some ultra-zoom digital cameras with compact design, so far, there is no ultra-zoom digital camera weighing less than 200 grams. SLR cameras are suitable for the following people: 1. Professionals; 2. Quasi-major. Amateur, pay attention to image quality; 3. Want to find a movie feeling; 4. People who like this kind of camera.