Digital camera pixels are generally better.

Abstract: How many pixels is a digital camera? The higher the pixel, the better? The maximum pixel number of digital camera, effective pixel number of digital camera, pixel setting of digital camera and the comparison of developing photo size are described in detail. How many pixels does a digital camera have? Is the pixel of a digital camera as high as possible?

Although digital camera has gradually become the first choice for photographers, its rapid development is only a few years. At the beginning of the birth of digital cameras, pixels are a brand-new thing for many people. Even now, many beginners don't understand this. In order to help those novices who have just set foot in the field of digital photography better understand digital cameras and master digital photography, here is a brief introduction to the pixels of digital cameras.

Pixel, translated from English pixel, is the abbreviation of Pictureelement, which is the number of points in a unit area that constitute an image. Each pixel has a different color value. The more pixels per unit area, the higher the resolution and the better the image effect. Pixels are sometimes called pels (short for picture elements).

How many pixels does a digital camera need?

How high a pixel camera you choose depends on the purpose. Even at home, different people or at different times will have different uses.

1, look at it on the computer. The number of pixels of a display with full HD resolution of 22 inches or more is1920×1080 = 2073600 (a little over 2 million). So chinafoxana's friend said 3 million is enough. Online photos don't need to be larger than the whole screen.

2. develop the photos. There are many 5-inch ones and many 7-inch ones at home. 7-inch photo, more than 3 million pixels is really enough. The larger the photo area, the more pixels are needed. In my opinion, it is usually enough to develop small ones. Sometimes we also want to develop some photos into large ones, so we need to leave some margin.

3. If you want to edit an image, the purpose of editing is different, and the requirements for the number of pixels are also different. As long as you don't print or spray, the requirements are not high. Nowadays, most new camera products, even low-end products with low prices, are above100000 pixels. Therefore, it can meet the requirements of household for the number of pixels. In other words, you don't have to consider the number of pixels when you buy a camera.

Is the pixel of a digital camera as high as possible?

It is not that the larger the pixel, the clearer the picture. It depends on the size of CCD and the area of photosensitive device of digital camera, including CCD and CMOS. The larger the area of photosensitive device, the larger the CCD/CMOS area, the more photons captured, the better the photosensitive performance and the lower the signal-to-noise ratio. CCD/CMOS is an element used for photosensitive imaging in digital cameras, which is equivalent to the film in traditional optical cameras. The surface of photosensitive elements on CCD has the ability to store charges and is arranged in a matrix. When its surface feels the light, it will reflect the charge to the components, and the signals generated by all the photosensitive components on the whole CCD constitute a complete picture.

If you decompose CCD, you will find that the structure of CCD has three layers, the first layer is "microlens", the second layer is "dichroic filter" and the third layer is "photosensitive layer".

The first layer of "microlens"

We know that the key to digital camera imaging lies in its photosensitive layer. In order to expand the lighting rate of CCD, it is necessary to expand the light receiving area of a single pixel. However, the method of improving the lighting rate is also easy to reduce the image quality. This layer of "microlens" is equivalent to adding a pair of glasses in front of the photosensitive layer. Therefore, the photosensitive area is no longer determined by the opening area of the sensor, but by the surface area of the microlens.

The second layer is a "dichroic filter"

The second layer of CCD is the "dichroic filter". At present, there are two color separation methods, one is RGB primary color separation method, the other is CMYK complementary color separation method. These two methods have their own advantages and disadvantages. First of all, let's understand the concepts of two color separation methods. RGB is a method for separating three primary colors. Almost all the colors that human glasses can recognize can be composed of red, green and blue. The three letters of RGB are red, green and blue respectively, which shows that RGB color separation is formed by adjusting the colors of these three channels. Let's talk about CMYK, which is composed of four channels of colors, namely cyan (C), magenta (M), yellow (Y) and black (K). In the printing industry, CMYK is more suitable, but its adjusted color is not as much as RGB. The advantage of primary color CCD is sharp image quality and true color, but the disadvantage is noise. Therefore, we can notice that the ISO sensitivity of digital cameras that generally use primary color CCD will not exceed 400. In contrast, complementary color CCD has a Y-yellow color filter, which pays more attention to color resolution, but sacrifices the resolution of some images. On the ISO value, complementary color CCD can tolerate higher sensitivity, which can generally be set above 800.

The third layer: photosensitive layer

The third layer of CCD is the "photosensitive plate", which is mainly responsible for converting the light source of the filtered color layer into an electrical signal and transmitting the signal to the image processing chip to restore the image.

The film size of the traditional camera is 35mm, the diagonal length is 35mm, and the photosensitive area of the 35mm film is 36x24mm. When converted into a digital camera, the diagonal length is about 35mm, and the larger the CCD/CMOS size is. In SLR digital cameras, many have CCD/CMOS dimensions close to 35mm. For example, Nikon D 100, CCD/CMOS size area reaches 23.7x 15.6, which is much larger than consumer digital cameras, while Canon EOS- 1Ds CMOS size is 36x24mm, reaching an area of 35mm, so the imaging is relatively good. There are four kinds of consumer digital cameras in the market: 2/3 inch,11.8 inch, 1/2.7 inch, 1/3.2 inch. The larger the CCD/CMOS size, the larger the photosensitive area and the better the imaging effect. 11.8-inch 3-megapixel camera is usually better than 1/2.7-inch 4-megapixel camera (the light-sensitive area of the latter is only 55% of the former). The increase of CCD/CMOS pixels with the same size is a good thing, but it will also lead to the decrease of the photosensitive area of a single pixel, which may lead to underexposure. However, in order to increase the number of CCD/CMOS pixels while maintaining the existing image quality, it is necessary to increase the total area of CCD/CMOS on the basis of at least maintaining the area of a single pixel. At present, it is difficult to manufacture larger CCD/CMOS, and the cost is very high. Therefore, the larger the CCD/CMOS size, the more expensive the digital camera is. The size of the photosensitive device directly affects the volume and weight of the digital camera. The CCD/CMOS size of ultra-thin and ultra-light digital cameras is generally relatively small. The more professional digital cameras are, the larger the CCD/CMOS size is.

The pixels of a digital camera are divided into the largest pixel and the effective pixel.

Maximum pixel:

The English name is MaximumPixels, and the so-called maximum pixel is obtained by interpolation. Interpolation operation through the DSP chip inside the digital camera, when the image needs to be enlarged, the pixels that need to be added after the image is enlarged are added by using the nearest neighbor interpolation, linear interpolation and other operation methods. The image quality obtained after interpolation operation can't be compared with the real photosensitive image.

Some merchants in the market will mark "XXX pixels can be realized by hardware interpolation", which is the same principle, but from the perspective of image quality and sensitivity, photos taken with the largest pixel are not as clear as those taken with effective pixels.

The largest pixel also refers directly to the pixel of CCD/CMOS photosensitive device. In order to increase sales, some businesses only promote the maximum pixel of digital cameras. When setting the picture resolution of digital cameras, they do take pictures with the highest pixel resolution. However, users should be aware that this is the value obtained through internal calculation of digital camera, and the loss of image quality will be very obvious when printing pictures.

Effective pixels:

EffectivePixels are called effective pixels in English. Different from the largest pixel, the effective pixel number refers to the pixel value that really participates in photosensitive imaging. The value of the highest pixel is the real pixel of the photosensitive device, and this data usually includes the non-imaging part of the photosensitive device, while the effective pixel is the value converted under the zoom magnification of the lens. Take Minolta's DiMAGE7 as an example, its CCD pixel is 5.24 million (5.24 megapixels). Because some CCDs do not participate in imaging, the effective pixel is only 4.9 million.

Digital pictures are generally stored in pixels, and each pixel is the smallest unit in digital pictures. The larger the pixel, the larger the area of the picture. To increase the area of a picture, if no more light enters the photosensitive device, the only way is to increase the area of pixels, which may affect the sharpness and clarity of the picture. Therefore, under the condition of constant pixel area, the digital camera can get the largest picture pixel, which is the effective pixel.

When users buy digital cameras, they usually see the merchants promoting "the maximum pixel reaches XXX" and "the effective pixel reaches XXX", so how should users choose? When choosing a digital camera, we should pay attention to the effective pixel number of the digital camera, and the value of the effective pixel number is the key to determine the picture quality.

Digital camera pixel setting and print photo size comparison table;

The comparison table between the pixel settings of some digital cameras and the best photo size that can be printed can be selected according to the photo size you want to print. If you want to print your digital photos into general specifications (the current mainstream digital printing is 5R, that is, 5x7 inches), then 3 million pixels is enough.

At present, the number of pixels of commonly used digital cameras is usually between 2 million pixels and 8 million pixels. The maximum size of photos taken in the mode with higher pixels of digital camera can be larger without distortion, but there is no difference between digital photos with more than 3 million pixels in terms of photo clarity. Therefore, in order to save the space of digital camera memory card when traveling, it is not necessary to take pictures according to the maximum pixel setting. For example, a 5-megapixel digital camera can also be set to a 3-megapixel camera, so that more photos can be taken on the same card.

The following is a comparison table of pixel settings of some digital cameras and the best photo size that can be developed. You can choose to use it according to the size of the photos you want to develop.

Pixel setting of digital camera

Photo file resolution (pixels)

Optimum photo size for printing

5 million pixels

2560× 1920

& gt12r (12×18 inch)

4 million pixels

2272× 170

8R(8× 10 inch)

3 million pixels

2048× 1536

5R(5×7 inches)

Two million pixels

1600× 1200

5R(5×7 inches)

65438+500,000

1280× 1024

4R(4×6 inches)

Pixel setting and print photo size comparison table

From the above comparison, it can be seen that if you want to print your digital photos into general specifications (the current mainstream digital printing is 5R, that is, 5x7 inches), then 3 million pixels is enough. 3 million pixels (2048X 1536) can print photos of 10R (that is, 10x 14 inch), but the effect is slightly worse. If your digital photos are just browsed on the computer or posted on the website, even setting them to/kloc-0.0 million pixels is enough. However, with the increase of the memory card capacity of digital cameras, the memory card of 5 12M is generally set to 3 million pixels, which can generally take more than 400 photos, so it is more reasonable to choose 3 million pixels for future printing.