What are the advantages of the mirror structure in SLR?

The advantages of adopting mirror structure in SLR are as follows:

1, SLR mirror structure means the use of pure optical viewfinder, the biggest advantage is that compared with electronic viewfinder, the framing picture has no time lag, "what you see is what you get." The electronic viewfinder mode is somewhat delayed.

2. Independent autofocus detection module and photometry module can be installed in the light path behind the reflector. The response speed and accuracy of focusing are high. The auto-focus detection point of electronic viewfinder is often included in the sensor. When the pixel per inch of the sensor is too high, the focusing response speed tends to slow down. Sensitivity is also reduced.

3. In order to improve the autofocus performance, some single cameras also adopt a semi-transparent mirror structure. For example, a55/77/99, a brand of single camera, belongs to this kind of mirror structure, and an autofocus detection module and a photometer module are set in the reflected light path to improve the autofocus performance. This kind of semi-lens structure can avoid the time spent in the process of mirror turning and mirror withdrawing, and the continuous shooting speed can easily reach 10 frames per second. However, this semi-transparent mirror structure makes the light reaching the sensor lose about 10%. Film SLR once appeared semi-transparent mirror SLR, but it is only a single camera in the digital age, and digital SLR has not been adopted.