Compare the characteristics of traditional cameras and digital cameras

At present, there are two main differences between digital cameras and traditional cameras.

First, real-time and convenience, which digital cameras have the upper hand; Second, the resolution. General digital cameras currently have a maximum of 4 million pixels, and traditional cameras have more than 20 million pixels, so traditional cameras have the upper hand. However, with the continuous progress of technology, it is just around the corner for digital cameras to replace traditional cameras.

First, focus and focus

1, shutter

The shutter is like a window, which controls the time when the light enters. If the light enters for too long, it will be overexposed, and if it is too short, it will be dark. At present, digital cameras have not used real shutters. In order to obtain high-quality images, digital technology is combined with mechanical shutter.

2. Hole

The aperture adjusts the amount of light entering, and the smaller the aperture, the less light entering. Both of them use mechanical parts to adjust the aperture size.

Step 3: lens

The light is refracted by the lens and focused on the negative or CCD. Both are almost the same, both can use fixed lenses with long depth of field, and both can focus clearly. Some digital cameras can also take some close-ups beyond the fixed focal length limit.

4. Film sensitivity

The more sensitive (faster) the film is, the faster it reacts when it touches the light source. A negative with lower sensitivity will have higher resolution and the ability to record image details. At present, the built-in CCD of digital cameras only has the same sensitivity, just as most traditional cameras use ASA 100( 100 degree) film. However, the built-in chip can adjust the sensitivity of CCD independently.

Second, the photosensitive process

The traditional negative film is formed by silver halide emulsion layer, which produces photochemical reaction to incident light.

Digital camera CCD is a surface chip composed of thousands of photosensitive electronic sensors. It will first convert light energy into electronic signals and then into digital information, which is a way of image electronization. The sensor on CCD will react differently according to the light intensity. The brighter the light, the stronger the electronic signal. After combining light intensity and color, the digital camera can set each pixel to a specific color by converting it into a pixel.

Third, the principle of development

1, traditional camera

After chemical action, silver halide becomes pure silver ion, and the less exposed part is more transparent; Then the negative is fixed to avoid further chemical reaction and develop into a negative with opposite black and white. After the negative is reversed, strong light shines through the negative on the photographic paper with the photosensitive layer, so a photo comes out.

2. Digital camera

A digital camera uses the image sensing function of CCD (Charge Coupled Device) to convert the light reflected by an object into a digital signal, which is compressed and stored in a built-in memory chip (RAM) or a portable PC card.

The difference between digital camera and traditional camera lies in the way of responding to light and the form of negative film. Digital cameras use CCD to sense light, while traditional cameras can record images through photochemical reactions generated by negatives.

With the maturity of technology, today's digital cameras and traditional cameras have reached the same level. When digital cameras can be equipped with more and more memories and more and more sensors on CCD, high-resolution image presentation and convenient and economical image storage will no longer be a dream.