What are the advantages and disadvantages of digital photography?

Advantages and disadvantages of digital photography

Digital photography conforms to the general trend of the information age, and has many advantages compared with traditional chemical film, such as vertical shooting, image editing, complete fidelity reproduction, convenient retrieval and transmission, etc. Vertical photography is obvious. Press the shutter and you can see the effect immediately, unlike traditional film, which has to wait until it is developed or even developed. Image editing is also widely known with the popularity of "computer portrait". After taking pictures, you can change the background, clothes, hairstyle and even make up for the defects. Digital photo is a kind of data file, which is very convenient to retrieve. It can be copied at any time without distortion or sent through the computer network, which may be the most difficult thing for traditional photography. With the renewal of people's ideas, "photos" don't have to be printed on paper, and electronic photo albums are gradually accepted by the public. These advantages will be more obvious. What this paper is going to discuss is not these obvious advantages, but a deeper level, that is, the advantages and limitations of digital photography in expressiveness. In other words, what kind of subjects digital photography is best at and what it is not suitable for.

The tool of digital photography is a digital camera, and the heart of a digital camera is an imaging chip. Today, it is a color CCD. The only difference between digital photography and traditional photography is that traditional photography records image signals on film, while digital photography records image signals as data files through CCD. CCD is a device for quantifying image information, which uses a series of data to describe the color and brightness of every detail of the image. Comparatively speaking, traditional chemical imaging is an analog recording of the subject, and the recording of color is not only related to the shooting process, but also depends on the performance of the film itself and the change of temperature or chemical properties during the development and printing. It may make the final result unrecognizable. Because digital photography records colors quantitatively, the color of pixels is a definite value. As long as the display or output device is adjusted according to the standard, the effect of each display or output is very close. For images with rich colors but smooth transition, the image processing software can calculate the transition color close to the truth, so as to carry out undistorted interpolation and amplification. Therefore, the advantage of digital photography lies in the perfect color reproduction, which is very suitable for using continuous colors instead of lines or points as elements to represent objects.

There are advantages and limitations. The so-called limitations, of course, are compared with the traditional chemical imaging-film. Before discussing the limitations of digital photography, we might as well know something about chemical imaging. The imaging unit of chemical imaging is at the molecular level. After carefully designing the shape of imaging chemical particles and perfectly controlling various process parameters, almost any image that can be distinguished by a lens can be recorded. When expressing color images, the film adopts the method of three-dimensional layering. The cross-sectional structure of ordinary negative film is shown in the following figure, and the reverse film is similar to this, but the performance of each layer is different. When imaging, each latex layer only reacts with one of the three primary colors to generate its complementary dye, so the color separation of multiple colors that make up a certain point is overlapping, and the resolution and clarity of the image will not be reduced because of color separation.

In contrast, the CCD imaging unit of a digital camera is an electronic component with a certain physical volume, so it is impossible to be as small as a molecule, which limits the resolution of digital photography. In addition, when forming color images, CCD adopts plane segmentation method. The structure of common G-R-G-B CCD is shown in the left figure below. When photosensitive, each photosensitive unit records the color value of a primary color. When processing signals, RGB values are calculated from four points of a-b-g-h and recorded as one pixel. At the same time, B-C-H-I and G-H. Although this method skillfully solves the problem of recording color signals, its shortcomings are also very obvious. First of all, because the color value of each pixel is calculated by several adjacent photosensitive units (note that the concepts of "pixel" and "photosensitive unit" are used here to express the difference), the resolution and sharpness of the image will inevitably decrease, and because the photosensitive points that make up a pixel are not exactly the same in physics, there is a certain displacement, which brings errors. If the color and brightness of two adjacent areas are the same or change continuously, they can be recovered correctly. If there is a big difference, there will be a big error in the calculation. The demarcation point doesn't know where to go, so it's just a rough idea. Therefore, digital photography is not suitable for complex color points and interlaced lines.

Chemical film is only exposed when shooting, and the imaging process is carried out in the later development. So as long as the mechanical speed can keep up, high-speed continuous shooting can be realized. However, it takes some time to process and record the data of digital camera after shooting, especially when the shooting accuracy is high, the amount of data is very large and it takes longer. Although this problem can be alleviated by increasing the internal cache, it cannot be fundamentally solved, so it will be very inconvenient to shoot with a digital camera. Because there are many factors affecting the chemical imaging process, which are uncontrollable and unpredictable, it may produce various unexpected artistic effects and greatly increase the charm of photography. The standardization of digital images greatly improves the controllability and predictability of the imaging process. On the one hand, this is a great advantage, which can faithfully express the photographer's intention, but it may become a major limitation in artistic creation, which greatly limits people's creativity.

The cost of digital photography is relatively low, and friends who have the conditions can handle it themselves.