Don’t assume that look on their face is shame—Amish don’t use the judicial system and some take it to the extreme of contempt due to their religious beliefs. Further, if your society said that having your photograph taken would get you shunned/send you to Hell because it is Hochmud (fancy/vain), you’d avoid eye contact with the camera to protect yourself from the temptation and nervousness regarding the whole unfamiliar process of this picture taking.