I won't leave Sony e slot for the time being. Because Sony's original 70-200 has only one F4 at present, which is relatively light and has a slightly smaller aperture, and then it is 70200GM, which is slightly more expensive. There are only these two models in e-port, so there is no choice.

Sigma 70-200 is a wide-angle peripheral camera suitable for mainstream cameras or digital cameras. Cameras generally have basic functions such as video shooting, transmission and still image capture. After the image is collected by the lens, it is processed by the photosensitive element circuit and control element in the camera and converted into a digital signal that can be recognized by the computer.

Then input the camera into the computer through parallel port or USB connection, and then restore the image through software. The lens is composed of several lenses, usually plastic lenses or glass lenses. The more lenses, the higher the cost; Glass lenses are more expensive than plastic ones. Camera pixel is one of the important indicators to measure the camera.

In practical application, the higher the pixel of the camera, the better the image quality, but conversely, the higher the pixel, the better. For the same picture, the higher the pixel, the better the image analysis ability. However, the amount of data it records will be much larger, so the requirements for storage devices are also much higher, so the mainstream products should be adopted when choosing.