In sports, researchers often use stroboscopic photography, as shown in Figure A, which is a photo taken by stroboscopic photography.

(1) Because the clothes worn by people are rough and uneven, the light emitted by the light source diffuses to the athletes;

② The lens of the camera is a convex lens, which is made by the principle that the convex lens is inverted and reduced when u > 2f. The focal length of the convex lens is 5cm. When the distance between the person and the camera is more than twice the focal length, that is, more than 10cm, it can be inverted and reduced.

③ The light parallel to the main optical axis will pass through the focal point after being refracted by the convex lens; The light passing through the focal point is refracted by the convex lens and parallel to the main optical axis, as shown in the following figure:

So, the answer is: people; True; 10.