Help! ! ! Please have a look at the master photographer!

There must be a black box behind the perforated cardboard. Black box production and film installation are the problems. Self-control is not easy, so it is recommended to transform the old camera. Do you have an old-fashioned mechanical SLR camera? Take off the lens and fix it on the bayonet of the fuselage (adhesive tape, double-sided tape and other methods can be used, as long as there is no light leakage). Use a piece of black cardboard (or a thin metal plate, such as can skin, which is opaque except for the hole in the middle, not thick) as the lens of pinhole photography. Install the film normally, fix the tripod, take a view, release the cable and lock the door B for exposure (the pinhole is too small and the exposure time is too long). According to the diameter of the pinhole, the corresponding aperture is estimated, and the time is determined by combining the failure factors of reciprocity law. To be sure, it doesn't matter if it's a few minutes apart. In this way, handing in homework should not be a problem.