I like cameras! Who can introduce it?

Single lens reflex (SLR) is the most popular viewfinder system. Most 35mm cameras use this viewfinder. 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. Therefore, you can accurately see the same image that the film is about to "see". The core of the system is a movable mirror (as shown in the light blue part), which is placed in front of the film plane at an angle of 45. The light entering the lens is reflected upward by the mirror to a piece of ground glass. Early SLR cameras had to hold the camera waist-high and look down at the ground glass. Although the image on the ground glass is upright, it is upside down. In order to correct this defect, the current eye-level SLR cameras are equipped with a pentaprism above the frosted glass. This prism reflects light many times to change the light path and send the image to the eyepiece. At this time, the ground image is upright up and down, and corrected left and right. When framing, most of the light entering the camera is reflected upward by the reflector to the pentaprism. Shutters of SLR cameras are almost always directly in front of the film (because they are located in the film plane, they are called focal plane shutters). When framing, the shutter is closed and no light reaches the film. Press the shutter button, the reflector quickly turns up to get out of the way, at the same time, the shutter opens, the light reaches the film, and the shooting is completed. Then, the mirrors in most cameras will be reset immediately.

[Edit this paragraph] Problems with SLR cameras

This necessary tilting action of the mirror also brings some other problems: First, the viewfinder will be blocked when taking pictures. Because the shielding time is only a moment, this is not a big problem for the image that is reset immediately. However, it also raises some emergency issues. For example, when using stroboscopic shooting, you will not be able to see whether the stroboscopic device flashes normally through the viewfinder. Second, the noise of the mirror moving. This may become an important problem where silence is needed. Because there is no moving mirror that suddenly blocks the light path in the ranging camera, this noise will not be generated. Third, the vibration of the camera, that is, the overall movement of the camera caused by the tilting action of the mirror. Suppose you shoot at a shutter speed of 1/500 seconds, don't worry. This vibration will not be detected. However, if you take accurate photos at a low shutter speed, such as with a telephoto lens in low light, this vibration may cause great problems in imaging. In addition, there is another problem with SLR framing. For example, if we want to shoot with a small aperture like f/32, the light allowed into the lens by f/32 is very weak, which will cause the image seen in the viewfinder to be blurred, and it may be difficult to focus or even impossible to focus at all. In fact, the solution of SLR is quite clever. It will first use the maximum aperture of the lens to complete the framing and focusing. When the shutter is pressed, the aperture of the lens will immediately shrink to the preset aperture to complete the film exposure. At the moment when the exposure is completed, the aperture will be opened to the maximum aperture to prepare for the next shooting.

[Edit this paragraph] Digital SLR technology

First of all, let's learn what a digital SLR camera is. To put it bluntly, a digital SLR camera is a digital camera adopting new SLR technology. As a professional digital camera, the photos taken with it are incomparable in definition and quality. These are the high performance of digital SLR cameras made by SLR technology. Single lens reflection. The camera using this technology has only one lens, which is responsible for photography and framing. This can basically solve the problem of poor photo quality caused by parallax. Moreover, when a SLR camera is used to view a scene, the light emitted by the object is focused by the lens, reflected by the inclined reflector to the focusing screen for imaging, and then reflected by the "roof prism" raised at the top. Photographers can observe the scene through the viewfinder eyepiece, and it is the same image as the scene, which is convenient for framing and focusing. When shooting, the mirror will bounce up immediately, the lens aperture will automatically shrink to a predetermined value, and the shutter will open to make the film sensitive; After exposure, the shutter is closed and the aperture of the mirror and lens is reset at the same time. This is the SLR technology in cameras. Now digital cameras have become professional digital SLR cameras after adopting this technology. The single-lens reflective framing method basically means professional positioning, which also doomed the professional road of digital SLR cameras. Even products for ordinary users and enthusiasts have many advantages.

[Edit this paragraph] The working principle of digital SLR camera

DSLR, digital SLR camera, or digital SLR camera, refers to a single-lens reflex digital camera, that is, digital digital, single-lens lens and reflex. Its photosensitive device is CCD or CMOS. This kind of camera is usually big and heavy. In the working system of SLR digital camera, after the light reaches the reflector through the lens, it refracts 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. Working principle diagram of SLR camera When shooting in DSLR, when the shutter button is pressed, the mirror will bounce 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 mirror 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. In the SLR 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 passes through the lens and reaches the reflector, and then refracts 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 illumination light passes through the lens (1) and is reflected by the mirror (2) to the frosted viewfinder screen (5). Through the total reflection in the convex lens (6) and the pentaprism (7), the final image appears in the view 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 photographed on the CCD(4), which is consistent with what is seen on the viewfinder screen.

[Edit this paragraph] The main features of digital SLR cameras

Digital SLR camera A major feature of SLR digital camera is that it can replace lenses with different specifications, which is an inherent advantage of SLR cameras and incomparable to ordinary digital cameras. In addition, SLR digital cameras are now positioned as high-end products of digital cameras, so the area of photosensitive elements (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.

[Edit this paragraph] Several reasons for choosing digital SLR.

The professional positioning of digital SLR cameras determines that even popular products for ordinary users and enthusiasts have many advantages, which is also the fundamental reason why many enthusiasts choose digital SLR cameras. We can summarize the professional characteristics of digital SLR as follows:

1, advantages of image sensor

CMOS image sensor For digital cameras, the photosensitive element is one of the most important core components, and its size is directly related to the shooting effect. To achieve good shooting results, the most effective way is not only to increase the number of pixels, but also to increase the size of CCD or CMOS. Whether using CCD or CMOS, the sensor size of digital SLR cameras is much larger than that of ordinary digital cameras. Therefore, the number of sensor pixels of digital SLR is not only relatively large (at present, the minimum is 6 million), but also the area of a single pixel is four or five times that of a civil digital camera, so it has a very good cost performance and can record a wide brightness range. The image quality of a 6-megapixel digital SLR camera definitely exceeds that of an 8-megapixel 2/3-inch CCD camera.

2. Rich lens selection

Digital camera is a product of optical, mechanical and electrical integration, and the performance of optical imaging system is also very important to the final imaging effect. Having an excellent lens is as important for imaging as the choice of image sensor. At the same time, with the cost reduction of image sensor, image engine and storage equipment, the proportion of optical lens in the cost of digital camera is also increasing. This is especially true for digital SLR. In the choice of traditional SLR cameras, the richness and imaging quality of lens groups are important factors in the choice of film friends. In the digital age, the retention rate of lens group naturally becomes the basis of brand competition. Canon, Nikon and other brands have huge autofocus lens groups, from super wide angle to super telephoto, from macro to soft focus, users can choose matching lenses according to their own needs. At the same time, due to the large sensor area, it is easier for digital SLR cameras to obtain excellent imaging. More importantly, many photographers generally have one or two or even a dozen professional lenses, all of which are purchased by photographers with their hard-earned money. If they buy a digital SLR camera body, the lens will be revitalized at once, and they will form two complementary film and digital systems with the original traditional film camera.

3. Fast response speed

The biggest problem of general digital cameras is the long shutter lag. If you don't master it well, you will often miss the most wonderful moment. Response speed is the advantage of digital SLR. Because their focusing system is independent of imaging equipment, they can basically achieve the same response speed as traditional SLR, which makes users handy in news and sports photography. At present, Canon's EOS1D Mark Ⅱ and Nikon D2H can reach the continuous shooting speed of 8 frames per second, which is comparable to traditional film cameras.

4. Excellent manual control ability

Although the camera's automatic shooting function is getting stronger and stronger today, a user who has certain requirements for photography will not be satisfied with shooting only in automatic mode because of the ever-changing environment and shooting objects. This requires that digital cameras also have the ability of manual adjustment, so that users can adjust according to different situations to achieve the best shooting effect. Therefore, the function of manual adjustment has become an essential function of digital SLR and a professional representative. Exposure and white balance are two important aspects in many manual functions. When the automatic metering system cannot accurately judge the light and color temperature of the shooting environment, users need to judge according to their own experience and make mandatory adjustments manually to achieve good shooting results. This is also the embodiment of the professionalism of digital SLR. For example, EOS 10D can adjust the color temperature value on the basis of 100K every time to help users get the best effect.

5, rich accessories

An important difference between digital SLR and ordinary digital camera is its strong expansibility. In addition to continuing to use additional lenses such as polarizers and interchangeable lenses, you can also use auxiliary equipment such as professional flashlights to enhance your ability to adapt to various environments. For example, high-power flash, ring macro flash, battery handle, timing remote controller, these rich accessories make digital SLR adapt to various unique needs, while ordinary digital cameras are greatly inferior.

[Edit this paragraph] How to choose a digital SLR camera

Is DSLR (Digital Single Lens Reflective Camera) a must for ordinary family players? DSLR digital SLR is the pursuit of professional users (journalists, photographers) and photographers! Compared with consumer-grade DC, there is a big gap between DSLR and consumer-grade DC: DSLR brings larger dynamic range (signal-to-noise ratio), replaceable lens, better imaging quality, shorter shutter lag, faster operation and processing speed, more realistic framing, faster continuous shooting speed and more professional control, which are incomparable to consumer-grade DC. The biggest problem is that the size and weight are larger than those of consumer digital cameras, and accessories such as lens flash filter make digital cameras inconvenient to carry. The second problem is that the CCD/CMOS chip of digital SLR camera is easy to be contaminated with dust. Olympus E- 1 can remove the dust on the surface of CCD/CMOS chip by ultrasonic device, but other brands of digital SLR cameras are still helpless to dust, which seriously affects the imaging quality and service life. Therefore, Sony F828/ Minolta A2/ Fuji S7000 and other quasi-professional digital cameras will still have strong vitality due to the convenience of "traveling around the world with one mirror", although they are facing a huge blow from the public SLR digital cameras. 1. although there are some "selling points" differences in technical details, it can be considered that there is no difference in essence and no need to study it carefully. 2. Focusing speed, shutter lag and continuous shooting speed are very important for news photography, sports photography, wildlife photography and snapshot photography. For digital SLR cameras, the improvement of performance is accompanied by a sharp increase in price. 3. Life of the fuselage The shutter life of a general SLR camera is 50,000 times, the life of a high-end SLR camera can reach 8-65438+ 10,000 times, and the longest life of a professional SLR camera can reach more than150,000 times. In practical use, if the high-speed continuous shooting function is often used, the shutter life will be reduced. The service life of LCD screen is about 1000 hours. Reflective framing system is a component that affects the life of digital SLR cameras. Frequent and high-load use can easily lead to the failure of reflective frame system. 4. The camera with high reliability will be dustproof, waterproof and impact-resistant. Because of the metal body and special materials, the price of such a camera will be high. 5. Color space In addition to sRGB as the standard color space for Windows and inkjet printers, you can also choose Adobe RGB, which is more widely used. You can choose the best color space according to the purpose of photography. 6. Flash system For professional photographers, the metering and exposure system of flash is very important. In the automation of flash system, each manufacturer has its own unique skills. There is no best or worst, only the best. 7. The advantage of lens group digital SLR camera is that it can change lenses. Whether the original lens series support and the products of independent lens manufacturers are rich enough to meet your needs is a problem worthy of attention. 8. Do you support W/A reading and writing acceleration technology? All digital SLR cameras released after the fall of 2003 will support W/A reading and writing acceleration technology. With this technology, the speed of reading and writing CF cards can reach more than 40 times (6MB/S). 9. Transmission Interface Digital SLR cameras released after the fall of 2003 should have both USB2.0 and 1394 firewire terminals. Some cameras should also support wireless network transmission such as 802. 1 1b/g and Bluetooth. 10. Photosensitive sensitivity and noise suppression Higher sensitivity and better noise suppression are our pursuit. 1 1. Shutter Maximum shutter speed and slowest shutter speed (B-door) are two key indexes of digital SLR camera shutter. The reliability and accuracy of the shutter also need attention. The highest flash synchronization speed is also a sign to measure whether a digital SLR camera is advanced or not. 12. whether the handle, shape and weight of the fuselage are suitable or not is often the most important place to decide to buy a SLR camera. Regardless of the price, the size and weight of professional digital SLR cameras are not acceptable to everyone. Small and lightweight amateur digital SLR cameras are more suitable for ordinary people. 13. Psychology often plays a decisive role in the end, and rational consumption is very important. Summary: At present, digital SLR cameras are monopolized by a few manufacturers, and it is an absolute truth in the field of digital SLR cameras to get what you pay for. In order to meet the high-load and high-intensity professional photography, it is best to choose an expensive digital SLR camera. If it's just hobbies and fun, it's best to choose economy.

[Edit this paragraph] Supporting equipment and its procurement guide

1, lens maintenance tool

For the whole camera, the lens is the most easily damaged component. In order to protect the lens, ultraviolet lens is essential. In addition, lens paper, lens brush, blowing tube and lens cleaning solution are all common tools for cleaning lenses. Fuselage maintenance tools In the maintenance of the whole fuselage, a camera bag is also essential. In addition to the camera, you can also put batteries, various lenses, memory cards, lens paper and other items. Common brands include LOWEPRO, JENOVA, PAULL, etc. The prices of foreign brands are generally more expensive. For example, a camera bag with a commonly used specification of 22cm× 15cm× 18cm for digital cameras generally needs to range from 200 yuan to 300 yuan, so it is quite practical to buy a domestic camera bag with good quality, and the price is much cheaper.

Step 2: tripod

Tripod tripod is known as "the most practical shockproof system in the world". Indeed, tripod plays a very important role when the lighting environment is not satisfactory. For users with high-end consumer digital cameras, tripods are needed in many occasions. It is very practical when shooting night scenes. The macro and light environment are poor and it is easy to shake hands. There are also many tripods on the market now. For lightweight digital cameras, the requirements for choosing a tripod are not very high. You can buy a good tripod around 300 yuan.

Step 3 flash

Although digital cameras now basically have built-in flash, the number and effective flash distance of flash can't be compared with external flash, and external flash can also provide users with more creative space. On the other hand, if the built-in flash is used more in shooting, the battery life will undoubtedly be greatly shortened. Because the external flash uses an independent power supply, it will hardly consume the power of the camera when shooting with the external flash. In digital cameras, there are very few third-party manufacturers specializing in flash, so basically you can only buy flash from the original camera.

4. Range extender and wide-angle lens

Many users often feel that the wide angle is not big enough or the telephoto is not long enough after using their own digital cameras. If you are often worried about the limitations of your camera lens, then I suggest you buy a suitable rangefinder or wide-angle lens as soon as possible. But don't buy blindly. If you often use telephoto and don't mind a smaller wide-angle end, then you can buy a rangefinder with a suitable multiple. On the contrary, buy a wide-angle lens. Of course, if both ends need to be expanded, you have to buy two. At present, most of the extended-range lenses and wide-angle lenses sold in the market are produced by third-party manufacturers, and the prices range from 150 yuan to 1000 yuan, and the original ones are more expensive.

5. Storage media

SD card At present, the memory cards used by digital cameras include CF card, SD card, MMC card, xD card and memory stick. For home users, it is more appropriate to have a 2GB or 4GB memory card as needed. For enthusiasts who often go out to shoot, considering that the storage media are cheap now, of course, the more the better. The storage medium with 180 GB may be normal. After all, no one wants to take pictures and delete them one by one in playback mode. There is also a digital camera storage king on the market, which is small in size, large in capacity and low in unit price. It can also directly read various memory cards, so users who need to go out for a long time can pay attention to it.

6. Battery

If you can continue shooting by deleting some photos after shooting the memory card of the digital camera, then the use of the battery is not so simple. A digital camera can't live without batteries, and it also consumes a lot of batteries. From this point of view, buying a battery is more troublesome than buying a memory card. For digital camera users who use AA batteries, they may have less trouble. After all, the price of rechargeable batteries on the market is relatively cheap, and the price of four batteries can generally be bought around 60 yuan. For digital camera users who use dedicated lithium-ion batteries, it is recommended to buy another battery, preferably the original battery.

[Edit this paragraph] How to learn the use of SLR cameras?

1, for amateurs

1. Communicate with related movie friends and participate in activities such as shooting outside; 2. Look at photos, exchange stickers and learn from each other in related photography forums; 3. Buy relevant books for systematic study, such as "Extraordinary Photography Notes-Playing SLR Camera for 2 Days" (Electronic Industry Press, 2065438+00.3);

2. For professional users

1. Go to relevant photography schools for training; 2. Learn from famous teachers. Any camera has its advantages and characteristics. The key is how to use it skillfully and give full play to it. Let's talk about the basic settings and parameters of a SLR camera. Photo size and format: Advanced cameras have uncompressed format (RAW, TIIF), which is convenient for later adjustment (professional software). But the file is so big that ordinary people don't need it. We usually use JPG format, and the storage method (compression) is very good, and the general sum is poor. I suggest you save it in the best way (less compression and good image quality). As for the photo size, it can be divided into three types (large, medium and small). If you want to print photos in the future, it is enough to use the largest pixel, generally online communication (convenient for later cutting). If the memory card is too small and you want to take more photos, you have to use a small one. Sensitivity: this is a parameter left by the film, reflecting the sensitivity to light. The lower the sensitivity, the better the image quality. The higher the exposure you need. The higher the sensitivity, the less exposure is needed, which can improve the shutter speed. But the picture quality is not good, contradictory! General picture quality is set to the lowest (ISO: 50- 100). When the light is too dim and the shutter speed is too slow, we have no choice but to improve the sensitivity in order to prevent jitter. Generally, the maximum exposure mode of a camera does not exceed 400, and the SLR does not exceed 800 (related to the area of the photoreceptor): advanced cameras generally include automatic, program (P), shutter priority (S), aperture priority (A), scene mode, etc. And ordinary cameras are the least. Automatic is often called an idiot, without any parameter adjustment, just take photos casually. The program can adjust some parameters (such as sensitivity, flash), and some cameras can also adjust the aperture shutter combination under the program. These are only suitable for beginners, easy to use and convenient. Scene mode is specially set for beginners, including portraits, landscapes, night scenes and so on. If different modes are used in different environments, the camera will automatically have different aperture shutter combinations to achieve the best results. Some people with basic photography usually give priority to aperture. You can adjust the aperture at any time according to the different light of the scene (aperture has a great relationship with special effects such as depth of field), and the camera will automatically set the shutter speed. Zoom: After other settings, you can take pictures. First, zoom, zoom in (wide angle, short focal length) or zoom in (telephoto) to form the picture you need. General cameras have 3-5 times optical zoom, and advanced cameras also have 7- 15 times zoom. For example, 35- 140mm is a 4x zoom. Optical zoom changes the focal length by moving the inner lens of the lens. Digital zoom is of little practical significance, which is equivalent to the amplification of processing software and has an impact on image quality. Focus: Don't confuse it with zoom. In order to shoot a scene at any distance clearly, you must focus. Generally speaking, when you half press the shutter, the camera will automatically complete it and prompt you with color or sound. When the light is dark, or when the contrast is small, the focus is slow or even out of focus. At this time, it is necessary to focus on the auxiliary light (usually self-contained, automatically turned on) or manually (advanced cameras have manual function). There are generally three modes of focusing (multi-point focusing, center focusing and point focusing). Multi-focus is generally not recommended. Focusing is fast, but it is easy to lose focus. That is, you want the scenery in the middle to be clear, but either the front or the side is clear, and the result is blurred. Generally, center focusing is commonly used. Aim the center focus frame at the scene you want to shoot, press the shutter halfway, and don't let go of your hand when there is a prompt of successful focus. Adjust the camera angle to the picture you want, and then press the shutter completely to take pictures, and there will be no problem. Be careful not to move back and forth and change the distance. Otherwise, we need to refocus. Point focusing is more accurate, mainly used when the depth of field is very small and macro shooting. Some cameras can also move the focus position. After the composition is completed, if you can't move the camera, you can move the focus to where you need it. Photometry: Nowadays, cameras set exposure automatically, so photometry is related to the accuracy of exposure. There are generally three kinds of photometry (average photometry, center photometry and spot photometry). Average photometry, also called multipoint photometry, can be used for general scenery, which is convenient and accurate. Central metering is used for close-ups or backlighting. Focusing the center on the main scene can ensure the accuracy of the exposure of the central scene, without worrying about excessive (white) or insufficient (black) violence around it. Spot metering is a small area metering, which is mainly used for macro or special requirements and is not easy to master. For example, taking a close-up of a person, aiming the metering point at black eyes, will definitely be too violent in the face. If you aim at the bright spot of the nose, the others must be black. Many cameras' spot metering is linked to focusing, just to focus on the main scene accurately and clearly. There are other unimportant parameters: white balance (auto), exposure compensation (0), picture style (contrast, sharpness, saturation), continuous shooting, delay (self-timer) and so on. Just look at the manual settings or factory settings. Whether a photo is successful or not, we must first ensure that the focus is clear, not blurred or shaken, and the exposure is accurate. Secondly, other factors such as composition angle and depth of field control are considered. Practice makes perfect. Digital doesn't cost money anyway. Practice more and take more pictures. Whether it is an advanced camera or an ordinary camera, you must first learn to use the half-press shutter. Only by mastering the camera in your hand can you make full use of the camera's function to express your ideas in your creation. Get a satisfactory job.

[Edit this paragraph] Main accessories of SLR cameras

1, ultraviolet lens

Filter the excess ultraviolet rays in the air and protect the lens. UV brands, such as; Baogu, Kengo, Hasen, B+W, and some original lenses of big brands, etc. Prices are also uneven: for example, from tens of yuan to hundreds of yuan. When you choose, you should pay attention to the coating on the surface of the UV mirror, especially when shaking under strong light, and seeing colorful colors, the light transmission performance is very good. Putting the camera in front of our eyes is a feeling that we can't see the camera. Moreover, lenses with tens of dollars are not strictly ultraviolet lenses (called protective lenses). First of all, the lens is not coated (there is no coating, and there is no function above the UV lens, just to protect the lens and prevent the lens from falling off). Putting them on the lens is like adding a piece of high-grade glass. The imaging effect is not as good as without lens.

2. Liquid crystal protective film

Mainly plays a role in preventing the LCD screen from being scratched. This protective film is used by electrostatic adsorption on the surface of LCD screen. If the surface of the protective film is seriously scratched after long-term use, it can be replaced in time, and it has no corrosive effect on the surface of the LCD screen. (The film used on the mobile phone sticks to the surface of the LCD screen and cannot be replaced. )

Step 3 blow

Clean the dust on the lens and camera surface, but be sure to pay attention to it when cleaning. The blow head must be at a distance from the lens, and blow hard through the palm of your hand (this can ensure that the blow head will not accidentally touch the lens, causing scratches on the lens.

4. Lens cloth

It should be used in conjunction with blowing. When wiping the lens, don't blow the floating ash on the lens with your mouth, so as to avoid saliva on the lens (especially after eating greasy things, once the lens is stained with greasy saliva, it is not easy to wipe it.

5. camera bag

First of all, the choice of camera bags should be selective (that is, what is the use of buying bags), such as rain, shock, dust and fire prevention. There are many kinds of camera bags on the market now: Jeep, Le Shebao, Weifeng, Buckingham, Nikko, Buster, Jiduoxi and so on.

Have fun!