What is dv? What is dc? What's the difference between them? Which is better and more practical to buy?

DV(Digital Video) literally means digital camera, but cameras have many storage media, generally referring to cameras that use miniDV video tapes, and other cameras that use hard disks, DVDs to burn CDs and memory cards. The main function of the camera is to shoot dynamic images, and taking pictures is only an auxiliary function.

DC (Digital Camera) literally means a digital camera, but it is actually a camera that records photos digitally, without using ordinary film, and its appearance is similar to that of ordinary cameras. Its main function is to take pictures. The so-called shooting dynamic images is only an incidental function, and the effect of the shot images is far less than that of the camera.

The above is a simple comparison.

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The difference between DC and DV

DC (Digital Camera) is a kind of digital camera, which is used to take a single still photo. DV (Digital Camera) is a kind of digital camera, which is used to shoot dynamic video images.

Simply put, DC and DV have their own uses, and each has its own emphasis. However, with the development of two kinds of products, there is a trend that the dynamic video recording function of DC is getting stronger and stronger, and there are also models that can take 2 million, 3 million pixels or even higher-precision DV still photos, and even Sanyo C series DC/DV two-in-one things. However, this kind of products is only a small part of many product lines, and the market performance is not very ideal. So what is the difficulty of DC shooting dynamic images or DV shooting static images?

The difficulty of DC as DV is that it is difficult to achieve high resolution at first, and then the cooperation of photoelectric system.

Let's talk about the first point: it is difficult to achieve high resolution. Although the number of pixels of digital cameras is as high as several million, and the number of pixels of a single image of dynamic video is only several hundred thousand, dynamic video has to record dozens of frames every second, and the total amount of data is very huge. The image processing chip of digital camera is specially designed for processing static pictures, and it is often difficult to process dynamic stream files, because the image processing chips of DC and DV are dedicated chips. Its "high efficiency" comes from "functional specificity", so we should take into account two aspects, either using a processor with more powerful computing power or sacrificing processing efficiency. The former means expensive, while the latter means low energy consumption. On the other hand, the huge amount of data requires huge storage space, so the mainstream DV still uses tape, because even if MPEG-4 format with high compression ratio is adopted, the 5 12MB memory card can only store high-precision video for more than ten minutes.

The second point: the cooperation of photoelectric system. When taking a single photo, you can zoom in advance. Accuracy is the first requirement, and you can even give up a little speed for accuracy. When shooting dynamic images, zooming, focusing and image shooting are carried out at the same time, which requires the cooperation of photoelectric system to be not only accurate, but also fast and even more accurate. Therefore, DC and DV have different requirements for the cooperation of photoelectric systems, so it is difficult to give consideration to both sides. Therefore, although many DCs can shoot video clips, they can't zoom in the middle of shooting, and many low-end models even lock the focus after the video starts.

The difficulty of DV as DC is still the resolution. Because people's visual perception is different, the requirement for the accuracy of dynamic images is far lower than that of static images. If the standard PAL and NTSC video signals are converted into pixels, the accuracy of a single picture is less than 300,000 pixels. The VGA-level video signal (640x480,300,000 pixels) is already of high precision. Even for HDTV, a single picture is only 2 million pixels (1920x 1080 pixels), so the current mainstream DV is still 800,000 pixels. As far as DC is concerned, the current 3-megapixel model has gradually withdrawn from the mainstream market, and household products have entered 5 million pixels.

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This is a very simple question, but it is not easy to say it thoroughly.

DC-digital camera, a kind of digital camera, used to take still photos; DV-digital camera, a kind of digital camera, is used to shoot dynamic images. Simply put, each has its own purpose and emphasis.

However, there is a trend now, that is, the dynamic video recording function of DC is getting stronger and stronger, and a digital camera like Casio EX-P505 has appeared, which is almost not inferior to special DV. In DV, there are also models that can take 2 million, 3 million pixels or even higher-precision still photos, and even products like Sanyo C4 and C5 that combine DC/DV. However, such products are only a small part of the huge product lines of DC and DV, and their market performance is not very ideal. So what is the fundamental difference between DC and DV? In other words, how difficult is it for DC to shoot moving images or DV to shoot still images?

Let's look at the difficulties of DC as DV. First, it is difficult to achieve high resolution. Although the number of pixels of digital cameras is as high as several million, and the number of pixels of a single image of dynamic video is only several hundred thousand, dynamic video records dozens of frames every second, and the total amount of data is very huge. The image processing chip of digital camera is specially designed for processing static pictures, and it is often a bit inadequate to process dynamic streaming files, because the image processing chips of DC and DV are dedicated chips, and their "high efficiency" comes from "single function", so we should give consideration to both sides or. On the other hand, the huge amount of data requires huge storage space, so the mainstream DV still uses tape, because even if MPEG-4 format with high compression ratio is adopted, the 5 12MB memory card can only store high-precision video for more than ten minutes.

Secondly, the cooperation of photoelectric system. When taking a single photo, you can zoom in advance. Accuracy is the first requirement, and you can even give up a little speed for accuracy. When shooting dynamic images, zooming, focusing and image shooting are carried out at the same time, which requires the cooperation of photoelectric system to be not only accurate, but also fast and even more accurate. Therefore, DC and DV have different requirements for the cooperation of photoelectric systems, so it is difficult to give consideration to both sides. Therefore, although many DCs can shoot video clips, they can't zoom in the middle of shooting, and many low-end models even lock the focus after the video starts.

Conversely, it is not easy to take still photos with DV. First of all, the resolution is the same. Because people's visual perception is different, the accuracy of dynamic images is much lower than that of static images. If standard PAL and NTSC video signals are converted into pixels, the accuracy of a single picture is less than 300,000 pixels. The video signal of VGA level (6.40x480,300,000 pixels) is already of high precision. Even the emerging HDTV has only 2 million pixels (6.6 million pixels) in a single picture. As far as DC is concerned, the current 3-megapixel model has gradually withdrawn from the mainstream market, and household products have reached 5 million pixels.

Even if an image sensor with high pixel count is used, the requirements for lens angles are different due to the different photosensitive areas used, otherwise Samsung's "DC and DV in one" product will not strangely install two lenses.

References:

2006-01-10: 21place of origin: 5 1CTO. Computer output microfilm