How can I set up a SLR camera to take pictures with blurred background?

1, the larger the aperture, the more virtual the background. Everything below F4 is considered as a large aperture. Such as: f3.5 f2.8 f 1.8 and so on.

2. The closer the lens is, the more virtual the background is.

3, the longer the focal length, the more virtual the background, as the saying goes: the aperture is not enough, the telephoto comes together. Anything over 55mm belongs to telephoto.

4. The farther the subject is from the background behind him, the more virtual it is.

Imaging principle of extended data SLR camera;

1. In this system, the unique design of the mirror and prism enables the photographer to directly observe the image passing through the lens from the viewfinder.

2. As can be seen from the structural diagram of the single-lens reflex camera, after the light reaches the reflector through the lens, it is reflected to the focusing screen above to form an image.

Through the eyepiece and pentaprism, we can see the scenery outside in the observation window.

The light passes through the lens and is reflected by the reflector to the frosted viewfinder.

3. After being reflected by convex lens and pentaprism, the final image appears in the view frame. When the shutter is pressed, the mirror moves in the direction shown by the arrow, and the mirror is lifted, and the image is taken on CCD or CMOS, which is consistent with what is seen on the viewfinder screen.

4. Compared with paraxial cameras, SLR cameras have the advantage that what you see is what you get, and the imaging angle in the viewfinder is the same as the final film.

References:

Baidu Encyclopedia-Single lens reflex camera