Is a SLR camera the same as an ordinary camera without a lens?

It is unscientific to often hear the saying "how about SLR".

1. What is "DC"?

DC-the abbreviation of digital camera, which is also the abbreviation of "digital camera".

DC is a concept opposite to a movie camera.

As we all know, film cameras include side-looking and reflective (single-lens and double-lens reflective) cameras. Similarly, digital cameras (DC) also include reflective and side-looking cameras. With the development of digital cameras, a new way of electronic framing has appeared in digital cameras, which is also through the lens, but does not use a reflector. (In addition, of course, there are also back-shot framing cameras mainly used for large and medium format cameras, so I won't discuss them here. )

DC or film is divided from the aspect of imaging media, and has nothing to do with the way of framing. SLR and sidelight are divided by the way of framing, which has nothing to do with the imaging medium.

As can be seen, DC is a mother concept, including single-lens reflex digital camera, side-looking digital camera, electronic camera and other sub-concepts. (Some of these cameras have not only one view mode, but also two view modes. For example, a pocket digital camera with an optical (side view) framing method can be used for optical framing and electronic framing through an LCD. Some SLR digital cameras can not only use pentaprism for optical framing, but also use LCD for electronic framing. )

Comparing SLR with DC means comparing the concept of mother with the concept of child, which obviously confuses the "levels" of these two different concepts. The correct statement should be: SLR digital camera (or SLR DC for short) and sidelight digital camera (or sidelight DC for short). Because some side-looking DCs have completely canceled the optical framing system, digital cameras with and without optical framing can be collectively called "portable DC" or "pocket DC", or simply "small DC". Second, you can correct the name of "SLR-like" without following the SLR.

In addition to SLR DC and portable DC, there is also a camera-DC similar to SLR, such as S 100 released by Fuji. As we know, this kind of digital camera is almost the same as SLR DC in usage habits, except that the mirror view is changed to electronic view. Because the camera's framing method is completely different from SLR's, there is no need to run behind SLR's ass, so it is called "SLR-like". It can be named according to its own framing method, and it is called a single-lens "electronic framing" digital camera (referred to as a single-lens digital camera or a single-lens DC-DSEV- digital single-lens electronic viewfinder), which corresponds to a single-lens DC(DSLR- digital single-lens reflex).

From this, we can divide digital cameras (DC) into three categories: pocket DC, SLR DC and single-person DC. Third, the characteristics of various DC framing methods

1. SLR DC

The advantages of Dan Toujing mirror frame are:

* Because the optical focusing system independent of the imaging module is adopted, its response speed is basically as fast as that of the traditional SLR camera, which makes it have obvious advantages in sports photography and capturing emergencies;

* Brighter and clearer than EVF and LCD viewfinder;

However, mirror framing is also flawed, otherwise why develop electronic framing on SLR digital cameras?

* There is an error in focusing accuracy. Because the imaging and autofocus detection of SLR DC are not in the same plane, defocusing is inevitable and it is difficult to solve it completely in theory. (The depth of field masks this problem to some extent. )

* Due to the barrier of the reflector, pure optical framing cannot provide real-time electronic framing, and it is impossible to view a large number of important shooting information such as image effect and histogram in real time, so that it can be corrected at any time, and photography is blind;

At present, this problem has been initially solved, but there is still a gap compared with single DC and portable DC. For example, the same CCD is used for framing and imaging. Because the reflector is raised during real-time electronic framing, the optical path is blocked, and the fast focusing AF can't work. Focusing and CCD zeroing should be carried out after the reflector falls, which increases the time lag of the shutter, thus losing the "fast" advantage of SLR. In fact, the SLR has become a non-SLR at this time. The scheme of adding an image sensor in the pentamirror avoids the above defects, but it brings new problems-the focus sensor and the imaging sensor are not the same CCD, and errors are inevitable. Because the optical framing range of the low-end SLR digital camera is not 100%, the framing range conveyed by the CCD that "shoots" the pentamirror has a certain parallax with the main CCD that images. Moreover, what is mentioned above is only the error of the framing range. Because the physical characteristics of the two CCDs used are difficult to be completely consistent, it is difficult to ensure that there is no color difference between the images seen during framing and the images actually taken. More importantly, the resulting focusing accuracy error. These problems, non-SLR digital cameras will not appear at all, and have obvious unique advantages;

* The current technology has not solved the defect of no video shooting function caused by the mirror structure, but I believe that there is no technical obstacle to solve this problem on the basis of solving the electronic real-time view;

* The vibration caused by the operation of the mirror has a negative impact on the image quality; This is an old problem that is not easy to solve. Although the problem is not serious, SLR enthusiasts who pursue high quality should not turn a blind eye to this problem alone.

* Working noise caused by rearview mirror vibration. This shortcoming is particularly obvious in situations where mute is needed;

* Because the reflector needs a certain space to work, the rear lens of the lens must keep a certain distance from the CCD. Theoretically, it has a bad influence on the image quality, and it is better to be as close as possible to the CCD non-SLR DC. There is no need to defend the SLR DC with the following advantages, because it is not the only advantage because of the reflector, and other camera types can also do it:

* Using larger image sensor, the image quality is excellent;

* With a large cache, you can achieve a high continuous shooting speed, even if it is set to RAW format, you can also have a fast continuous shooting speed;

* replaceable and rich lens system;

* Rich accessory system. There is no need to attack the SLR DC with the following defects, because these defects are not necessarily causal with the use of "mirrors", and other types of digital cameras may also have these defects if they also adopt the same design:

* Because the lens can be replaced, the exposed image sensor (CCD or CMOS) is easily polluted by dust;

* Expensive lenses;

* trouble changing the lens; 2. Non-SLR DC (including single DC and portable DC)

This kind of digital camera adopts electronic framing mode (some of them have side-view optical framing) and the structure of mechanical shutter+electronic shutter. Among them, the electronic shutter really controls the exposure time. In general, the mechanical shutter is normally open, so that light can directly reach the image sensor through the lens. CCD photosensitive imaging is the picture displayed on LCD or EVF display screen. You can take pictures through LCD or EVF. Press the camera shutter when composition and framing are finished. At this time, the mechanical shutter of the digital camera is closed, which prevents the light from reaching the CCD (like a calculator clearing, keep the CCD completely black and clear the residual optical signal on the CCD). )。 Then the shutter opens instantly, the electronic shutter works at the same time, and the CCD captures the currently acquired image and saves it in the memory card. This is the whole process of taking a photo with a non-SLR digital camera. Advantages of electronic framing:

* Imaging and focusing are in the same plane, with high focusing accuracy and no defocusing;

* Imaging and electronic framing use the same image sensor, without other errors such as parallax and chromatic aberration, and what you see is what you get;

* It was quite quiet when shooting, and there was almost no noise;

* easy to realize audio dynamic video recording function;

* Through EVF or LCD framing, you can watch the actual imaging effect at any time, and you can view rich information such as real-time histogram, which is convenient for modifying various settings at any time to ensure shooting;

* Without a reflector, the rear lens can be as close as possible to the CCD, which is conducive to improving the imaging quality;

* There is no vibration when the reflector works, which is beneficial to improve the image quality; Disadvantages of electronic framing:

* Because the CCD camera needs to be "cleared" to expose, the shutter time lag is long;

* The definition and brightness of the viewfinder are not as good as the current viewfinder. Non-SLR DC does not need to use the following advantages, because it is not an advantage not to use mirror framing, and mirror framing digital cameras can also have these advantages, if they want:

* Because the lens cannot be changed, the image sensor (CCD or CMOS) is not easily polluted by dust;

* It is very convenient for a mirror to travel around the world, avoiding the expensive investment of the lens;

* You can avoid the trouble of changing lenses; There is no need to attack non-SLR DC with the following defects, because there is no necessary causal relationship between those shortcomings and not using a "mirror" to view, and other types of digital cameras may also have these shortcomings, if the same design is adopted:

* The image sensor with relatively small specifications is adopted, and the image quality is sufficient;

* The cache space is small, so high continuous shooting speed cannot be achieved;

* Non-replaceable lenses;

* There is no rich accessory system.

* The volume and weight are relatively large; There is no need to criticize the image quality of a single DC, which is not the fault of EVF, but the problem of CCD area. If you don't believe me, replace the SLR DC with a 2/3 CCD, and the picture quality will be the same, not better than S 100. There is no rule that single-cell digital cameras can only use sensors with specifications below 2/3 inches. Therefore, a single DC can also be made into APS-C specification. The single DC uses APS-C CCD, and the picture quality is not worse than that of SLR DC, and it is also better than SLR DC, because it avoids the vibration of the mirror! And with the increase of the size of the image sensor, the physical aperture of its lens will inevitably increase, and the luminous flux will also increase, which is conducive to the improvement of image quality. At that time, the picture quality of the single battery will immediately make the SLR DC speechless, and then adopt the design of replaceable lens. What can SLR say?

There is no need to criticize that a single DC cannot replace the lens. Replaceable lens is not a patent of DC SLR, nor is it a fundamental feature of DC SLR. Its fundamental feature is "reverse". Single electricity can also adopt the design of interchangeable lens, which has nothing to do with the framing method;

There is no need to criticize the size and weight of a single DC. It is the same model as the DC SLR camera. Why should it be small and light?

There is no need to criticize the price of single DC. Since it is the same level as SLR DC, if the CCD specification is the same, why is a single DC cheaper than SLR?

Fourth, cancel the mirror-the general trend.

The history of human development proves that no technology can be brilliant forever. In the film era, because the film, the medium for storing images, must strictly prevent light leakage during framing, SLR skillfully uses reflector to solve the parallax problem of framing and avoid light leakage during framing. In the film age, SLR cameras pushed camera technology to the peak.

However, in the digital age, the situation has changed fundamentally-CCD is not afraid of light leakage! It can be used not only for framing, but also for imaging after clearing. Therefore, the necessity of reflector is greatly reduced. Its working principle determines that reflector framing is not suitable for digital photography. There is no need to keep a mechanical part-reflector on a fully electronic digital camera. Although people can tolerate the heavy and complicated structure of the reflector, because it can take into account the perspective through the lens and protect the film from light leakage, the existence of the reflector is no longer necessary, because in today's digital age, the image sensor is not afraid of light leakage, so people have no need to tolerate its heavy and complicated structure. With the improvement of electronic framing technology, one day, the clarity and brightness of electronic framing will be good enough to replace the reflector sooner or later. The dilemma is definitely SLR DC, because a single DC does not have an optical framing system, and a small DC with a side-view optical framing system can also cancel the optical framing system without any burden. No one will say anything about this. But the SLR DC is different-mirror framing is its fundamental feature, and once it is cancelled, it means the complete demise of SLR. If you don't cancel, you can only coexist with electronic framing. This is the foot of a snake. What's more, consumers have to pay more money for this snake.

The heyday of SLR was in the film age. At present, SLR has not withdrawn from the field of digital cameras for many reasons. For example, traditional camera manufacturers can use their own brands of massive lenses to establish their own competitive advantages; At present, the effect of electronic framing is not perfect, which also gives these manufacturers an opportunity.

In a word, it is the use of market and technical factors that leads to this situation. With the continuous development of technology, it is only a matter of time before SLR dies.

Some people who support SLR, in fact, did not use SLR in its heyday, but now SLR is beginning to decline. In fact, the SLR they admire has already passed its peak and started to decline.

It is hoped that the single-shot digital camera will develop rapidly in the direction of expanding CCD area, the first goal-APS-C format, and the final goal-full frame. At the same time, the design of replaceable lens is adopted.

When APS-C single camera was born, I hope you don't think that SLR cancelled the reflector. Don't make a mistake, it was the single camera that added CCD! Because, if the SLR really cancels the mirror, the SLR is not a SLR, and it completely denies itself.

Therefore, don't prematurely say that the status of a single battery is embarrassing because there is a low-end SLR DC in the world and a portable DC in the world-who will be embarrassed in the future? The history of human development proves that no technology is always brilliant. In the digital age, the single-lens reflex digital camera will decline and be replaced by "single-lens electronic framing digital camera", and this day will come sooner or later.

However, at that time, the SLR faction and the unipolar faction could stop fighting, and both sides could consider themselves victorious. Just like a few years ago, my alma mater, Nankai University, was planning to merge with Tianjin University, and the two sides could not reach an agreement on the name of the new school after the merger, so someone came up with a wonderful idea-"Tianjin Nankai University" to satisfy both sides' psychology. The merger of NTU and NTU was not realized in the end. I wonder if the "merger" of SLR and single electricity will become a reality?

Friends who want to pay for digital cameras don't have to be influenced by people who only pay attention to SLR. Our concept is going to change-you bought the latest camera representing the development direction of digital cameras-single battery DC, single lens electronic viewfinder digital camera! However, at present, there are few models with APS-C specifications for single battery DC, and APS-C image sensors are generally used for SLR or even full-width sensors. Therefore, there is still a gap between the image quality of single battery DC and SLR DC, which is only suitable for friends with "just right" consumption concept. Although young people have not grown up and become stronger, it is only a matter of time, and the future is theirs.

Single battery DC represents the development direction of digital cameras, just as traditional camera manufacturers announced that they would stop production of film machines after digital cameras developed to a certain level. With the development of single-battery digital cameras, sooner or later, camera manufacturers will announce that they will stop production of SLR digital cameras and instead produce all-battery digital cameras! Big CCD, of course. You can change the lens.