What does F+ mean in the camera?

What does the F+ in the camera mean? F+ stands for magnifying aperture.

Brief introduction: Camera, referred to as camera for short, is a kind of equipment that uses the principle of optical imaging to form images and records images with negative film. Many devices that can record images have the characteristics of cameras. Medical imaging equipment, astronomical observation equipment, etc. A camera is an optical instrument used for photography. After the light reflected by the shot scene is focused by the camera lens (scene lens) and the shutter for controlling exposure, the shot scene forms a latent image on the photosensitive material in the camera box, and forms a permanent image after being developed and fixed. This technology is called photography.

Digital camera is a kind of camera that uses electronic sensors to convert optical images into electronic data. Different from the principle that ordinary cameras record images through the chemical changes of silver bromide on the film, the sensor of digital cameras is a photo-sensitive charge-coupled {ZH-: device; Zh-: component }-(CCD) or complementary metal oxide semiconductor (CMOS). Before an image is transmitted to a computer, it is usually stored in a digital storage device (usually using flash memory; Floppy disks and rewritable compact discs (CD-RW) are rarely used in digital camera equipment.

Digital camera is a product integrating optics, machinery and electronics. It integrates the conversion, storage and transmission of image information, and has the characteristics of digital access, interactive processing with computer and real-time shooting. Digital cameras first appeared in America. More than 20 years ago, the United States used it to transmit photos to the ground via satellite. Later, digital photography was converted to civilian use, and its application scope continued to expand.

In order to get the shooting effect close to the traditional camera, improving the pixel resolution of CCD is the most fundamental solution. However, in the early days of the birth of digital cameras, it was difficult to talk about a higher level with pixels. In recent years, manufacturers have been struggling at the level of 300,000 pixels. It was not until 1988 that Canon introduced the RC-760 with 600,000 pixels.

What does ISO mean in the camera? ISO: sensitivity

Iso (International Organization for Standardization) international standard agreement: film sensitivity to light; Low sensitivity refers to films below ISO 50, medium sensitivity refers to ISO 100~200, and high sensitivity refers to films above ISO 400.

When using traditional cameras, we can choose negatives with different sensitivities (speeds) according to the brightness of the shooting environment. For example, iso200 can be used in cloudy environment, and iso400 or higher can be used in concert environment. Digital cameras have a similar function, which changes the iso value by changing the amplification factor of the signal amplifier in the photosensitive chip. However, when the iso value increases, the amplifier will also amplify the noise in the signal and produce a coarse-grained image.

A long time ago, there were contacts on the film that allowed the camera to automatically identify ISO. If you use a camera with the function of automatically identifying ISO film (there are metal beads identifying ISO in the film box), there is no need to set ISO, and the camera will automatically measure light according to the ISO value of the film. If you don't have this function, you need to set it manually, so some cameras have ISO dials on them.

Generally speaking, the price of ISO 100 film is relatively cheap. In addition to the higher price, the higher the ISO, there is another disadvantage, that is, the imaging quality is not as high as that of low ISO film. But sometimes in order to get higher shutter speed, the quality of the film will be sacrificed to use high ISO film.

ISO of digital camera is an index similar to film sensitivity. In fact, ISO of digital cameras is realized by adjusting the sensitivity of photosensitive devices or merging photosensitive points, that is, by improving the sensitivity of photosensitive devices or merging several adjacent photosensitive points.

Photosensitive devices have a kind of reaction ability and are fixed. Improving the ISO of digital cameras can be achieved in two ways: 1, forcibly improving the brightness and contrast of each pixel; 2. Using multiple pixels * * * can complete the task that only one pixel is needed.

It can be seen that the image quality loss of digital cameras after upgrading ISO is great, especially when the area of photosensitive devices is small, upgrading ISO is simply fatal. The CCD photosensitive area of FZ 10 or FZ20 is pitifully small, only 1/2.5 inches. If the ISO is upgraded, kill it. Therefore, some SLR digital cameras can still get good image quality after several ISO upgrades. This is because the CCD sensitive area of these cameras is relatively large, but it is not the scope of our discussion.

Depth analysis of ISO sensitivity of digital camera

I believe that the advantages of digital cameras are needless to say these days, but some open technologies inside digital cameras are still little-known secrets for ordinary digital enthusiasts. Slightly experienced color lovers can realize that in daily shooting, if the ISO sensitivity is improved, the originally dim environment can also jump on the LCD brightly. Although the lovely manufacturer has prepared 50 to 400 adjustable files for us, few friends really set it to ISO400. However, although the image quality of ordinary digital cameras is not good under ISO400, we find that digital SLR is still intact even if it is as high as ISO800.

How to realize random adjustable ISO sensitivity of digital camera? Feiyu answered these seemingly responsible questions in simple terms in line with the people-oriented scientific and technological concept.

First, the concept of ISO in the film age

ISO is the standard of film photosensitive speed formulated by the International Organization for Standardization according to the chemical reaction speed of film to light. As early as the film era, our photography life silently followed this industry standard. When buying film, the words ISO 100, ISO 200 and ISO400 will be marked on the package. The larger the ISO value here, the faster the photographic speed of the film, which means the film with high ISO value. Only weak light is needed to make the film produce an image, so that a smaller aperture or a higher shutter speed can be used under the same light brightness, that is, the sensitivity is inversely proportional to the required exposure.

For example, the exposure speed of ISO 100 is twice that of ISO 50, because the exposure time of ISO 50 is1125 seconds in the same situation. If ISO 100 film is used instead, it only takes1250 seconds.

Before explaining the principle that digital devices can adjust ISO sensitivity at will, let's learn about ISO in the movie era, which is believed to be helpful for us to understand the following. How do ordinary film cameras identify films with different ISO values? All secrets are based on DX coding system. The system was first used for disc film used in disc cameras, and later developed into 35mm film series, and was first applied to Kodak color film VR10/in1.Later, fujifilm, Konica, Germany, Akfa, Scotland and other large film companies adopted DX coding system.

At present, all color films produced at home and abroad have DX codes, which has become the symbol of modern films. As shown in figure 1, DX code consists of rectangular frame code of film cassette shell, with a total of 12 bits, and each bit is represented by a silver-white or black box for conduction and insulation. By reading this code, the film machine can automatically judge what film is loaded at the current photosensitive speed.

Second, the ISO principle of digital cameras

We don't need to change the film to change the photosensitive speed of the digital camera in shooting activities, we just need to adjust the ISO value in the camera. How to adjust ISO freely for digital cameras? I believe this is a problem that puzzles many digital enthusiasts. In order to understand this problem, we must first understand the signal transmission principle of the internal image sensor of the digital camera.

Signal transmission principle between 1 and CCD

As we all know, when the light passes through the lens and hits the CCD, the corresponding intensity of charge will accumulate under the photosensitive electrode. The amount of charge stored per unit depends on the light intensity received by the photosensitive unit. When we press the shutter release switch, the image electrical signal on each unit is transmitted to the analog-to-digital signal processing module (ADC/CDS). All these actions must be controlled by the pulse of the camera's internal image processor, which is usually divided into two transmission modes: mutual transmission and single transmission.

2. Popular understanding of 2.ISO principles

The sensitivity of traditional film is to change the sensitivity to light by changing its chemical composition, while the photosensitive element of digital camera is unchanged. Now let's get down to business and talk about the principle in a popular way. Digital cameras generally adopt the gain technology of electronic signal amplification, and the gain value of electronic signal amplification corresponds to ISO value, for example, it provides the gain amplitude equivalent to ISO 100 when set at the standard value, and the gain values corresponding to ISO200 and ISO 400 can be achieved by increasing the gain amplitude. So how is the gain amplitude achieved?

When providing high sensitivity, it is naturally necessary to provide corresponding gain amplitude, and the corresponding signal must be amplified before outputting the image signal, because the output level of CCD is low, especially when the ambient light is dark, in order to make the image change quantitatively, the amplifier will increase the gain amplitude according to the corresponding ISO value.

In addition, increasing the number of pixels in a given CCD area will make it difficult to maintain sensitivity. The area of unit pixel decreases and the intensity of incident light weakens. If a higher gain value is called to improve the ISO value, the image quality will deteriorate. Therefore, the lovely manufacturer provides a solution, which is to add the original image signal stored in CCD, which can improve the sensitivity relatively. Adding two pixel signals and transmitting them can double the original sensitivity. However, this working mode also has its disadvantages. It is only suitable for smaller image modes, because the number of pixels is halved during processing.

The third solution for the image industry to provide high ISO value is to take a few pixels as 1 pixel for photosensitive, so as to improve the photosensitive speed. As shown in fig. 5, for example, the standard ISO 100 is sensitive to each pixel of the photosensitive element. To improve the sensitivity of ISO200, only two pixels need to be treated as 1, and the original photosensitive speed can be doubled. If we want to improve to the level of ISO400, four pixels can be treated as 1 which can be four times as long. The difference from the second method is pixel merging, and the second method is the superposition of photosensitive signals, so this method has advantages for high pixel models, but the noise is more obvious than the first two methods.

Third, high ISO only brings noise.

The influence of sensitivity on photography is manifested in two aspects. One is speed. Higher sensitivity can get faster shutter speed and be easier to understand. The second is image quality. The lower the sensitivity, the finer the image quality, the higher the sensitivity and the higher the noise.

By the way, a concept-noise is introduced here, which mainly refers to the rough part of the image produced by CCD in the process of receiving and outputting light as a received signal. So how did the noise come from? First of all, we should understand that for a digital camera as an electronic product, the internal image sensor is bound to be subjected to different degrees of optical electromagnetic interference between peripheral circuits and its own pixels. In short, there must be some noise in the photos taken, which is inevitable. All we see is the degree.

For the first solution to provide high ISO value, the noise information is amplified while the gain amplitude increases, so the noise becomes more and more obvious in high ISO images. In the second way, as mentioned above, the number of pixels related to imaging will double while obtaining high ISO. In order to ensure that the original image information of the imaging size will be enlarged, noise will be generated. For the third scheme, due to the decrease of photosensitive pixels, only pixel interpolation can get a complete image in the process of white balance. I believe these three explanations are not difficult to understand. The popular "noise reduction function" in digital cameras aims to reduce the noise generated by the third solution.

It is no secret that digital cameras have variable ISO sensitivity. Although high ISO still makes us worry about noise, in order to get higher shutter speed and brighter picture, this is a compromise without increasing cost.

What does it mean in a graphic customizable camera?

Graphics can be customized.

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What does the s meter in the camera mean? Braking distance measuring instrument.

What does Ni mean in the camera? Nikon ...

What does 1.0x mean in the camera? The larger the number in front, the larger the zoom factor, and the farther the scene can be shot.

What does fps mean in digital cameras? FPS is the number of frames per second, which is translated from Chinese as the number of frames per second, commonly known as frame rate. Generally speaking, it means how many pictures are displayed in one second. The videos we see (movies, TV animated short films ...) are all composed of continuous freeze-frames The more pictures, the smoother the video and the larger the file space.

What does the f in the camera mean, such as f/8? F value is the aperture value, and f/8 is the aperture of 8.0.

Aperture is a device used to control the amount of light entering the photosensitive surface of the fuselage through the lens, usually in the lens. We use the f value to represent the aperture size.

Aperture f value = lens focal length/lens aperture diameter

As can be seen from the above formula, to achieve the same aperture f value, the aperture of a long focal length lens is larger than that of a short focal length lens.

The complete series of aperture values is as follows:

F 1, f 1.4, f2, f2.8, f4, f5.6, f8, f 1 1, f 16, f22, f32, f44, f64 and so on.

What does camera F mean? F does not refer to aperture-aperture refers to an adjustable multi-blade device that controls the amount of light entering the fuselage or lens.

The aperture size is expressed by f value. (also written as f)

This value is a series of numbers called the aperture coefficient of the lens (the reciprocal of the "relative aperture").

The values of complete aperture coefficient are: f 1, f 1.4, f2, f2.8, f4, f5.6, f8, f1,f 16, f22, f32, f44.

As for "what does camera F mean"-if it is printed on the body of Nikon, it means a series of models. I don't know what camera you are asking about.