What is a viewfinder?

the Viewfinder is the "window" for photographers to observe the scenery they want to shoot. Below we will introduce four kinds of viewfinder commonly used in digital cameras.

optical viewfinder

the optical viewfinder on a small digital camera is composed of a set of simple optical elements, which are connected with the optical system of the lens, so that the image in the optical viewfinder can be synchronously connected with the influence entering the lens. This viewfinder is small in size, but the biggest problem is the framing error. The viewfinder is usually placed above the lens, and the image seen from the optical viewfinder is different from the image projected by the lens on the sensor. In short-distance shooting, this "parallax" is more obvious. General optical viewfinder can only let users see 8% to 9% of the actual coverage of the lens. If you want to take an accurate view, it is better to use an LCD that ignores the difference. When using the optical viewfinder, friends who wear glasses had better check whether there is diopter adjustment next to the viewfinder, if there is, it will be much more convenient.

LCD framing of non-professional digital cameras

LCD framing of small digital cameras allows users to observe the image they want to shoot in real time, which is the same as the image projected by the lens on the CCD, and there will be no parallax. This way of framing is also called "TTL" (through-the-lens) framing TTL”(Through-The-Lens. But we know that it is very power-consuming to use LCD to take pictures, and it is difficult for us to see the pictures on the LCD when the sun is fierce. This urges us to use optical viewfinder or EVF viewfinder which will be discussed below. In addition, the LCD on the digital SLR is not used for framing. It only allows users to watch photos and operate menus on the LCD after shooting. Of course, DSLR has its own unique framing method, which will also be introduced below.

optical viewfinder (TTL) on digital SLR

A digital SLR that also uses an optical viewfinder has no parallax, because its optical viewfinder is more precise than a small digital camera, and its principle is to connect a mirror and a rhombus to the sensor, and the image projected by the lens onto the sensor is the image seen on TTL. When the photographer presses the shutter, the mirror will bounce up, the light will enter the sensor through the lens, and the sensor will start to expose. Due to the limitation of sensors, most digital SLR LCDs can only be used to watch photo playback, but not to take photos. There is usually a small LCD next to the DSLR optical viewfinder to display the camera's settings and status, such as aperture shutter, exposure compensation, white balance and so on.

EVF electronic viewfinder on a small digital camera

Electronic viewfinder actually transmits the picture on the LCD to the electronic viewfinder of the digital camera, so the image seen from EVF is the same as the image projected on the CCD by the lens, and it is synchronized with the image on the LCD. EVF is basically a small LCD (about .5' in diameter and about 235, pixels) above the lens, which allows users to take a more accurate view, especially in strong light without worrying about the difficulty of taking a view. EVF absorbs many advantages of digital SLR TTL viewfinder, such as no parallax, but it is impossible for cameras equipped with EVF to install optical viewfinder.