In the second week, we mainly learned about focal length.  Robin also showed us the phenomenon of longer number less thing and short number more thing through video operations.This reminds me that when I used to shoot, I usually only used one lens.  When you need to shoot close-ups or panoramas, you need to change the distance between the camera and the person.  So I thought it was unnecessary to use lenses with different focal lengths.  But with some practice, I found that it would be troublesome to shoot by changing the distance between the camera and the person.  For example, when shooting indoors, the limited space cannot allow the camera to have a proper distance from the person.  Or shooting in the same location with different cameras.  The different focal lengths of the lens are very important in these situations.I think that the choice of different lenses in the movie is not only to make the movie look more than a single picture, but also a way of expression.  When a close-up phenomenon is needed, it is to remind the audience to pay more attention to some emotional expressions or details.  For example, the following movie ‘Malèna’.  The first is a longer number less thing, and the second is a short number more thing.  My understanding of the first one is that this part focuses on the actor’s demeanor, so it is close up.The second focus is the reaction of the crowd when they look at the heroine, so the focus becomes shorter.