What is the relationship between pixels and SLR cameras?

1, the pixel is only related to the sensor of digital camera. All digital cameras have sensors, including double reflex, single reflex, no reflex (micro-single), paraxial, card machine and so on. And pixels have nothing to do with SLR.

2. There are two relationships between the pixel and the imaging quality of the sensor. First, it affects the SNR imaging index (SNR index) of the sensor, that is, on the basis of ensuring the basic number of pixels needed for imaging, the lower the total number of pixels, the higher the purity of imaging; Second, it affects the number of output frames (magnification size), that is, the higher the total number of pixels, the greater the number of output frames;

3. The imaging quality of digital camera is determined by lens, sensor and image processor. Among them, the imaging quality of the sensor is determined by A/D (analog-to-digital conversion) process and SNR (signal-to-noise ratio) process. A/D technology has nothing to do with pixels, and SNR involves pixels. SNR is the ratio of sensor area to the total number of pixels. In the case of the same sensor area or less total pixels, the higher the signal-to-noise ratio index of the image, the higher the signal-to-noise ratio index and the purer the image quality. The reason is that the larger the sensor area or the smaller the total number of pixels, the lower the pixel per inch of the sensor, and the larger the area of a single pixel, the better the photosensitive performance of a single pixel. When the photoelectric signal of the sensor is converted (the working principle of the sensor is to convert the light elements collected by the lens into electrical signals), it will inevitably produce less thermal noise (noise), and the imaging will be more stereoscopic and pure, such as 20 million pixels, and the imaging quality of Quan Huafu sensor will be higher than that of 1 inch sensor;

4. The less the total number of pixels in the same sensor area, the better the signal-to-noise ratio index and the higher the imaging quality, but the total number of pixels cannot be lower than the basic number of pixels. The so-called basic pixel number refers to the number of pixels required by the carrier used to display photos (images), such as 1080P display needs more than 2 million pixels, 4K display needs 8.3 million pixels, and printing A3 size pictures with the highest definition of 300DPI (retina standard) needs160,000 pixels. So the number of basic pixels varies with different carriers. In a specific carrier, more pixels beyond the basic pixels can not be displayed by the display carrier, nor can they be seen by the naked eye, which will also bring the side effect of reducing the signal-to-noise ratio. Therefore, the higher the pixel, the better, but on the basis of meeting the basic pixel number, the lower the pixel (mainly the pixel per inch), the better the image quality;

Although the lower the pixel per inch, the better the picture quality, but the high pixel still has the use of high pixel. For example, advertising photographers need high pixels when printing huge advertising images, and they also need high pixels when the images are greatly cropped. Therefore, for large pixels or high pixels, the requirements for different purposes are different.