What do you mean by viewfinder size and magnification in SLR cameras?

Magnification refers to the ratio of observing the opening angle of the subject to the eyes through the viewfinder to directly observing the opening angle of the subject to the eyes, that is, the ratio of the size of the subject seen through the viewfinder to the size of the subject directly seen with the eyes. The magnification of framing is large, the viewing angle is small, and the scenery seen during framing is close to the original object, which has a strong sense of reality.

The framing magnification is small and the viewing angle is large, so it is easy to see the panorama when framing. If the magnification is too small, it is difficult to observe the details of the object, which is not conducive to composition and focusing, and there is a great difference between the object and the image, which makes it very uncomfortable to take pictures. The magnification is generally less than 1X, mostly between 0.75 and 0.95 times. ..

The viewfinder size refers to the ratio of the scene range seen through the viewfinder to the scene range shot by the bottom film, expressed as a percentage. Generally, the picture seen from the viewfinder is not completely the shot picture, but always smaller than the shot picture, generally 90% ~ 100%. Therefore, SLR only basically avoids parallax, and only the framing range of 100% can be called no framing parallax. Usually only professional models have a visual range of 100%.

Magnification values in two cases. The magnification value at this time is the maximum magnification of this lens. For example, a lens with a focal length of 70-200mm has a nominal magnification of 1/6.5. That is to say, when the lens is shot with a focal length of 200mm and the shortest shooting distance for clear imaging, the ratio of imaging on the focal plane to the actual size of the subject is 1/6.5. The magnification of most camera lenses is less than 1, which means that the imaging of most lenses is actually reduced.