As we all know, digital camera shooting generally has two ways, one is through the liquid crystal display (LCD), the other is through the eyepiece viewfinder, the following description is the eyepiece viewfinder of the second digital camera. This type of viewfinder can be generally classified into: Separated from the lens, commonly referred to as an optical viewfinder Through the lens, commonly known as TTL viewfinder Electronic viewfinder, known as the Eye-level LCD viewfinder The first two viewfinders have many advantages over LCD viewfinders. First of all, it is possible to avoid excessive battery depletion due to turning on the LCD, which can increase shooting time and battery life. Second, when shooting outdoors, it can avoid the framing error caused by the reflection of the LCD screen. Let's take a closer look at the difference between the three viewfinders: 1, optical viewfinder Regardless of whether the camera's lens is fixed focus or zoom, the viewfinder of the optical viewfinder is the same, it does not work with the lens, it only simulates the perspective and focal length of the lens. Most home use point-and-shoot cameras (including home-use digital cameras) use this way of viewing. The size of the viewfinder into the light hole determines the clarity of the image, for users who wear glasses, there are relatively large holes are more important, because the glasses will make their eyes away from the viewfinder, This makes it impossible to accurately view the scene. Some viewfinders are now equipped with a diopter adjustment function that allows the photographer to take more accurate pictures without glasses. However, only near- and far-sighted people can perform refractive adjustment. For normal vision photographers, diopter adjustment is meaningless. The optical viewfinder should be as close as possible to the center of the optical axis of the lens to reduce parallax. The parallax occurs because the camera lens and viewfinder view the subject from different positions, so there is also some difference in the scenes they each see. In general, the optical viewfinder cannot display images taken with 100% of the lens, and it is probably only 85% or less of the actual frame. This is the reason for the development of a TTL viewfinder. 2, TTL optical viewfinder This viewfinder is usually equipped with a more expensive digital camera, it can display the image captured by the lens. In traditional film cameras, the vast majority have adopted this way of viewing. Different TTL framing systems work differently. When they are used, the details that can be displayed are not the same. However, they all reflect or scatter the light that passes through the lens to achieve framing. So for a digital camera using a TTL optical viewfinder, the images seen through the LCD screen and the viewfinder are the same. 3, electronic viewfinder This viewfinder has the same advantages as a TTL viewfinder: it displays the whole scene of the subject to be shot, can be seen under sunlight, and can display shooting information such as aperture and shutter speed, but in addition, it can also display the camera menu. This is not possible with other viewfinders. The disadvantages of the electronic viewfinder can be summarized as three: Unlike the optical viewfinder and TTL viewfinder, it requires a lot of power; similar to the LCD display, it is easy to reflect light, which affects the accuracy of the framing; it is rough compared with the optical system. The last item will be very important, because such a system cannot display the smallest details in the shot frame, such as whether the human eye is open or not.