I read an article at grammarbank , and understood that when we want to make personal passive for all of tenses we use "is thought (seen,said,...)" or "are thought (Seen,said,.. )",
but after that, over on baladre.info, I saw question number 6,
"Someone saw him pick up the gun"
and the answer is "He was seen to pick up the arm" .
So I am confused. Is the answer to the question correct? Shouldn't it be changed to "He is seen to have pick up the gun"?