When shooting a short video with the 5D2 camera’s short video function, the picture has a paper-like distortion. (It's like the picture is on a piece of cloth, and the cloth is distorted by the wind.

This is the jelly phenomenon

The jelly phenomenon occurs on photosensitive elements using CMOS (Panasonic LiveMOS is also based on CMOS technology). The data reading on the CMOS chip is a progressive scan photosensitive film. Sweep from the first line at the top to the last line at the bottom. . . If the scanning speed is not fast enough, during the continuous photosensitivity and continuous data reading process of video shooting, the data obtained from the first row at the top and the last row at the bottom will be out of sync, and the resulting video image will be shaken and distorted like jelly. Therefore, when using this type of equipment to shoot videos, you should try to keep the body as stable as possible.

The GH1 has jelly, the D90 has it, the D5000 has it, and the 5D2 has it. The degree depends on the circuitry and image processing algorithms that the manufacturer has equipped to alleviate this problem.

The worst jelly phenomenon is undoubtedly the mobile phone camera. If you don’t believe it, when you take the mobile phone to take a picture of the vertical stripe pattern, shake the lens hard. The result of shaking left and right is a snake-shaped distortion, and the result of shaking up and down is elongation or compression. , very fun.

CCD does not have jelly, because CCD reads the entire piece of data together. However, precisely because all data is read from one channel at the same time, CCD technology has a data bottleneck problem. Fortunately, in the standard definition era, the amount of high-definition video data is large, and the data reading speed of a single-chip CCD cannot keep up. This also reveals the reason why Panasonic insists on using 3ccd for home DV - to solve the problem of reading speed, not image quality. Therefore, although Panasonic's small home DVs use 3ccd, they are all small in size, and the overall picture quality is not as good as Sony or Canon's large-area single-chip CMOS.

In principle, professional equipment using similar photosensitive devices will also suffer from jelly, but professional equipment with strict requirements will use high-cost technology to reduce this phenomenon. And professional photographers generally try to avoid shaky shots. Technical flaws or not, wobbly shots are also highly visually objectionable.