光学防抖与电子防抖(Optical anti shake and electronic anti shake)
光学防抖与电子防抖(Optical anti shake and electronic anti
shake)
First of all, to understand why the development of "optical anti shake", because the SLR camera in shooting, inside the reflector will bounce, produce vibration, so need to shake, optical anti shake is because of this research and development. And the portable camera doesn't have this kind of vibration, and it doesn't need to be shaken when the light is good. So many years of film age, portable cameras (including Dummies) have been doing this. The installation of optical image stabilization in portable digital camera, is actually "head wearing a large hat", "overkill", but also for commercial speculation.
The need for electronic anti shake (referred to as high sensitivity) is produced in the film age of "dim light moving objects". The light should enlarge the aperture; the moving object should speed up the shutter speed. But each camera has a limit to the aperture, and the magnifying aperture will sacrifice the depth of field, and the dark will affect the exposure, so as to slow down the shutter speed, otherwise it will be insufficient exposure. In this case, fast film is needed to make up for GB24, ASA200, GB27 (ASA400) films. These films are fast enough to increase the speed of the shutter and take a dynamic picture.
In the era of digital camera, without using film, the sensitivity of the camera can be accelerated by using the sensitization of the camera's own elements, but the disadvantage is that it will affect the quality of the image.
If a digital camera has a high sensitivity (such as ISO6400), then the image loss is less. If the camera does not have high sensitivity, artificially improve the ISO, then the image loss will be greater.
Now the camera manufacturers are studying how to overcome the high sensitivity to image noise, once the successful research of electronic image stabilization technology will make a breakthrough.
Conclusion: optical anti shake is more practical for SLR camera and more advantage in shooting static object. And electronic anti shake is good for shooting dynamic objects, generally can meet the portable camera.
The camera will shake during exposure, and the photos will be virtual, but if you hold the camera to shoot, it is likely to shake during the exposure. Although some people can safely control the camera, and higher shutter speed can reduce the negative effects produced by the camera shake, but some dithering phenomenon and the resulting situation will send virtual image in handheld camera. And the longer the focus, the longer the exposure time, the more likely the handheld camera will take the blurred photos. Using a tripod to fix a camera is obviously an effective way to solve the shake of handheld photography, but the tripod is usually not very convenient to use, and is even forbidden in some cases.
In today's digital camera field, there are three main anti shake methods: lens optical anti shake, sensor displacement and high sensitivity anti shake, each of which has its own advantages.
The optical anti shake is the first one, and the latter two is electronic shake proof.
Optical anti shake:
Optical anti shake is a floating lens passing through the lens to correct the optical axis offset". The principle is to detect tiny movement through the gyroscope in the lens, and then transmit the signal to the microprocessor,
The processor immediately calculates the amount of displacement to be compensated, and then compensates the lens set, compensates the direction and displacement of the lens according to the jitter of the lens, thus effectively overcoming the image blurring caused by the vibration of the camera. The anti shake technology has high requirements for lens design and manufacture, and the cost is relatively high. Optical anti shake function effect is quite obvious, in general, open the function can improve the shutter speed of 2-3 files, the handheld shooting will not produce ambiguous phenomenon, for beginners, the effect is very obvious. Especially in the large zoom camera, the effect is more obvious, because the general zoom more larger, even very slight jitter is also very easy to see, for the case of telephoto anti shake function demand is bigger.
Electronic anti shake:
Electronic image stabilization using CCD offset to realize image stabilization, its principle is: first, the CCD can be placed in a next move around the bracket, and then when the gyro
sensor detects the jitter, the jitter will direction, speed and movement parameters after treatment, calculate the amount sufficient to offset the jitter of CCD mobile the. Compared with the optical anti shake technology, the CCD anti shake technology effectively avoids the spherical aberration caused by the compensation mode, and solves the limitation of the volume of the SLR camera. There is a kind of electronic image stabilization in high sensitive anti shake, some portable digital camera with high sensitivity and high anti shake, they support ISO sensitivity settings (some models can be as high as 3200) and when the light is insufficient to automatically increase the ISO setting function, so as to ensure a higher and more suitable for handheld shooting "the shutter speed.
But for any camera, shooting the image effect is better than high ISO low ISO effect, in order to counteract this effect, high ISO system usually collocation noise removal techniques to ensure senior picture quality.
Through the understanding of the anti shake function, we can know that the use of anti shake function, can effectively overcome the camera vibration caused by the image blur, so that handheld photography will not produce blurred phenomenon. Of course, the anti shake system will increase battery consumption, but not many.
In general, if you hold a shot, then use anti shake device! For telephoto or a character sketch at the telephoto end of the lens with long, anti shake is particularly useful. In addition, in some light dark environments, anti shake can also play a role.
Super shake proof refers to the optical anti shake plus high sensitivity dual anti shake, so that the picture is clearer, can effectively reduce the camera shake or movement of the object caused by blurred photos. For example, sell SONY's T20, this anti shake function is very suitable for beginners, generally speaking, the effect of electronic anti shake without optical anti shake effect is good.
As the optical image stabilization technology, and not let the body do not shake, it is to rely on special lens or the CCD photosensitive element in the structure to minimize the operator in use because of jitter image instability. Through the lens group to achieve anti shake is mainly to Canon and Nikon as the representative, they rely on magnetic suspension package lens, so as to effectively overcome the image produced by the camera shake blur, the zoom lens digital camera can play a more obvious effect.
Usually,
Gyroscope to detect the camera inside the tiny mobile, and will signal to the microprocessor immediately for calculating displacement compensation, and then through the compensation lens group, compensated according to the direction of the camera jitter and displacement, so as to effectively overcome the vibration generated by the camera image fuzzy.
Optical anti shake function effect is quite obvious, in general, open the function can be increased by 2 - 3 shutter speed, the handheld shooting will not produce ambiguous phenomenon, for beginners, the effect is very obvious, in addition to the
telephoto digital camera, the effect is immediate.
Electronic anti shake
Electronic image stabilization, is based on the analysis of the image on a CCD, then the edge image is compensated, like optical zoom and digital zoom, it is only the data was collected and processed, palliatives, not what the actual effect, on the contrary, there is a certain degree of damage to the quality. Currently, CASIO and Fuji are using electronic anti shake technology on the market. Consumers at the time of choice, the pursuit of anti shake function, must see clearly in the end is optical, or electronic, if it is electronic, you can consider giving up.
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