in pencil和with a pencil有什么区别么,麻烦讲清楚一点呢

in pencil 是说用铅笔写的；with a pencil 却不一定是写字；比如：He tried to pick it up with a pencil .再比如：a letter in pencil 是一封用铅笔写的信；而a letter with a pencil 是一封信和一支铅笔的意思....thanksa lot