How does Canon 60D shoot the effect of real before and virtual after?

The former is true and the latter is empty? What do you mean?

If the foreground is clear and the background is empty (of course, the subject is clear), it is necessary to adjust the distance of the foreground.

If the subject is clear and the background is empty, it is the problem of depth of field.

The so-called background blur means that the background is not within the depth of field.

Factors affecting depth of field:

One is the focal length of the lens. The greater the depth of field, the shallower the blur. It is difficult to blur the background at the wide-angle end.

The second is the aperture of the lens. The larger the aperture, the shallower the depth of field and the heavier the blur. If the maximum aperture is 3.5, etc.

The third is the shooting distance. The closer, the shallower the depth of field and the heavier the blur.

The fourth is to keep the subject away from the background, and the more vague the better.