What is a digital video camera?
Digital Video camera is DV, which is the abbreviation of Digital Video. Translated into Chinese, it means "Digital Video". It is a digital video format jointly developed by many famous home appliance giants such as Sony, Panasonic, Shengli, Sharp, Toshiba and Canon. However, in the joint development of a digital video format. However, in most cases, DV stands for digital camera. According to the purpose of use, it can be divided into: broadcast-grade models, professional-grade models and consumer-grade models. According to the storage medium, it can be divided into: magnetic tape type, optical disk type, hard disk type and memory card type.
Development course of digital camera
It has been 16 years since the first digital camera was born in 2011. During these 16 years, digital cameras have undergone tremendous changes. The storage media range from DV to DVD to hard disk, with a total pixel of 800,000 to 5 million, and the image quality ranges from standard-definition DV(720×576) to high-definition HDV(1920×1080).
The first DV camera was born in 1995.
In July, 1995, Sony released the first DV camera DCR-VX1000. Once released, DCR-VX1000 was widely adopted by TV journalists and producers all over the world. This product uses Mini-DV format tape, adopts 3CCD sensor (3 1/3 inch, 410,000 pixel CCD), 10x optical zoom and optical anti-shake system, and the price at the time of release is as high as 4,000 yuan. DCR-VX1000 is a major change in the history of imaging. Since then, civil digital cameras have entered the digital age.
The first DVD camera was born in 2000.
In August 2000, Hitachi introduced the first DVD camera DZ-MV100. At that time, this product could only be recorded by DVD-RAM. Hitachi first brought DVD as a storage medium into a digital camera, and used an 8cm DVD-RAM burning disc as a storage medium, which got rid of the inconvenience of DV tape and was a major innovation after DV camera. However, at that time, not many people paid attention to this product. DZ-MV100 was only sold in Japan, and it was hard to find a trace in the domestic market. It was recognized that DVD cameras should be widely promoted by Sony three years later.
In 2004, the first micro hard disk camera was born.
In September, 2004, JVC launched the first batch of 1-inch micro hard disk cameras MC200 and MC100, and the hard disk began to enter the field of consumer digital cameras. The capacity of the two hard disks is 4GB, and the video images taken are compressed by MPEG-2, so users can flexibly change the compression rate to extend the shooting time. The adoption of hard disk media makes it extremely convenient for digital cameras to exchange information with computers. Both MC200 and MC100 and several subsequent 1-inch micro hard disk cameras can flexibly replace micro hard disks. By June, 2005, JVC released the Everio G series with 1.8-inch high-capacity hard disk camera. The maximum capacity reached 30GB, and the volume was well controlled, and the price remained at the level of similar DV cameras.
In 2004, the first HDV 1080i HD camera was born.
In September 2003, Sony, Canon, Sharp and JVC jointly formulated the HD camera standard HDV. In September 2004, Sony released the first HDV 1080i high-definition camera HDR-FX1E. The recording resolution of HDV reached 1440×1080, and the horizontal scanning line was doubled compared with that of DVD, and the definition was revolutionized. HDR-FX1E, including the HDV cameras introduced later, used the original ones.
In 2010, the first 3D camera was born.
Up to now, the 3D revolution has all revolved around Hollywood blockbusters and major sports events. With the advent of Panasonic HDC-SDT750 3D camera, this technology is one step closer to home users. Panasonic HDC-SDT750 is the world’s first 3D camera. After the launch of this camera, we can capture every unforgettable moment of life with 3D lens in the future, such as children’s first step, university graduation celebration and so on. Panasonic released the HDC-SDT750 3D camera on July 28th, 2010. The official price is RMB 11,998 (excluding 3D lens). It is designed with dual lenses and equipped with Panasonic’s high-end series of 3mos image sensors. (What is a 3D camera? )
Working principle of digital camera
The basic principle of digital camera is simply the transformation and transmission of optical-electrical-digital signals. That is to say, the light signal is converted into current through the photosensitive element, and then the analog electric signal is converted into digital signal, and the information obtained after processing and filtering by a special chip is restored to be the dynamic picture we see.
The photosensitive element of digital video camera can convert light into charge, which is converted into digital signal through analog-to-digital converter chip. There are two main types: one is widely used CCD (Charge Coupled Device); The other is CMOS (complementary metal oxide conductor) device.
Characteristics of digital camera
High-definition analog cameras record analog signals, so the image definition (also called resolution, resolution or resolution) is not high. For example, the horizontal definition of VHS cameras is mainly 240 lines, and it is best to mention that Hi8 models only have 400 lines. DV records digital signals, and its horizontal resolution has reached 500~540 lines, which can be comparable to professional cameras.
The bandwidth of chroma and brightness signal of DV is almost six times that of analog camera, and the bandwidth of chroma and brightness is one of the most important factors that determine the image quality, so the color of the image shot by DV is more pure and gorgeous, and it has reached the level of professional camera.
The signal recorded on the lossless reproduction DV tape can be transcribed countless times, and the image quality will not be degraded at all, which is beyond the reach of analog cameras.
Small size and light weight Compared with analog cameras, the size of DV cameras is greatly reduced, generally only about 123mm×87mm×66mm, and the weight is greatly reduced, generally only about 500 grams, which greatly facilitates the users’ size is only 74.7mm×61.9mm×26.9mm and the weight is only 90 grams, which is even lighter than most mobile phones.
Digital camera classification
I. Classification according to the purpose of use
1. Broadcast-grade models:
These models are mainly used in the field of radio and television, with high image quality and comprehensive performance, but with higher price and larger volume, they have the highest definition, the largest signal-to-noise ratio and the best image quality. Of course, the price of several hundred thousand yuan is not acceptable to ordinary people. For example, Panasonic AJ-HPX3100MC and other models.
2, professional models:
These models are generally used in professional TV fields other than radio and television, such as audio-visual education, and the image quality is lower than that of broadcast cameras. However, in recent years, some high-end professional cameras have surpassed the old models of broadcast cameras in many aspects, such as performance indicators, and the price is generally between tens of thousands and hundreds of thousands of yuan.
Compared with consumer models, professional DV is not only cooler and more eye-catching, but also much higher in configuration, such as the use of lenses with better quality performance and the larger size of CCD, which is more prominent in imaging quality and adaptability to the environment. For friends who pursue image quality, the surprise brought by the improvement of image quality can’t be measured by money at all. Such as Sony’s HXR-NX5, the price is around 34,000.
3. Consumer-grade models:
This type of camera is mainly suitable for home use, and it is used in non-business occasions with low image quality requirements, such as home entertainment, etc. This type of camera is small in size, light in weight, easy to carry, simple in operation and cheap in price. It can be used to make VCD and DVD of personal family in occasions with low requirements, and the price is generally in the order of several thousand yuan to ten thousand yuan. Such as Sony’s HDR-XR160E.
If we subdivide the home digital cameras, they can be roughly divided into the following categories: entry-level DV, mid-range consumer-grade DV and high-end quasi-professional DV products.
Second, according to the classification of storage media
1, tape type:
Refers to the digital video camera with Mini DV as the recording medium, which was first developed by more than 10 manufacturers in 1994. Record high-quality digital video signals through a 1/4 inch metal vapor deposition tape.
2, CD-ROM:
Refers to the DVD digital camera, the storage medium is DVD-R, DVR+R, or DVD-RW, DVD+RW to store dynamic video images, which is simple to operate and easy to carry, and there is no need to worry about overlapping shooting during shooting, let alone wasting time to rewind or play back, especially it can be played immediately through the DVD player, which saves the trouble of post-editing.
DVD media has the highest security and stability among all media digital cameras at present. It is neither as easy to wear and tear as tape DV, nor as demanding as hard disk DV for shock prevention. The disadvantage is that the price of DVD is slightly higher than that of tape DV, and the time for recording is relatively short.
3, hard disk:
Refers to a digital video camera that uses a hard disk as a storage medium. It was first introduced by JVC in 2005, using micro hard disk as storage medium.
Hard disk cameras have many advantages, and large-capacity hard disk cameras can ensure long-term shooting, so that you will not have any worries when traveling. When you get home, you can transfer the shooting materials to the computer, and you no longer need the complicated and professional video acquisition equipment as in the era of MiniDV tape camera. You can easily export the materials just by connecting with the computer through USB cable, so that ordinary family users can easily experience the fun of shooting and editing video films.
Like CF card, micro hard disk is smaller than DVD, and its service time is the most impressive among many storage media. However, due to the short time of hard disk DV, there are still many shortcomings, such as poor shock resistance and so on. With the further decline of prices, the number of people in need will inevitably increase in the future.
4. Memory card type:
Refers to the digital video camera using memory card as storage medium, such as the popular "X Easy Shooting" product. As a transitional simple product, it is rare in the market now.
Three, according to the type and number of sensors.
1. Sensor types: CMOS and CCD.
CCD: Charge Coupled Device image sensor, which is made of a high-sensitivity semiconductor material, can convert light into charge, which is converted into digital signal by an analog-to-digital converter chip.
CMOS: Complementary metal-oxide semiconductor, like CCD, is a semiconductor that can record light changes in digital cameras.
At the same resolution, CMOS is cheaper than CCD, but the image quality produced by CMOS devices is lower than CCD. So far, most consumer-grade and high-end digital cameras on the market use CCD as sensors; CMOS sensors are used in some cameras as low-end products, but some high-end products also use special CMOS as light sensors, such as several high-end CMOS models of Sony.
2. Number of sensors: single CCD and 3CCD.
The number of image sensors is the number of CCD or CMOS sensors of digital cameras. Most digital cameras use a single CCD as their sensors, while some middle and high-end digital cameras use 3CD as their sensors.
Single CCD means that there is only one CCD in the camera and it is used for photoelectric conversion of brightness signal and color signal. Because a CCD completes the conversion of brightness signal and chroma signal at the same time, the captured image can not meet high requirements in color reproduction.
3CCD, as its name implies, is a camera using three ccds. We know that if light passes through a special prism, it will be divided into three colors: red, green and blue, and these three colors are the three primary colors used in our TV. Through these three primary colors, all TV signals including brightness signals can be generated. If a CCD is used to receive each color and convert it into an electrical signal, and then an image signal is generated after circuit processing, a 3CCD system can be formed, which can display the primary colors of the image almost intact, and there will be no color error caused by camera deduction.
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If you want to see more digital camera products, please click the following link:
Complete collection of digital cameras: //product.pconline.com.cn/dv/
Complete collection of high-definition cameras://product.pconline.com.cn/dv/c11107/
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