1) You can say look at the camera. It's fine to say it like that.
2) to photograph can be used as a verb, depending on how you use it in a sentence, example "I want to photograph someone" or "I'm going to photograph him".
3) look into is used in many situations, such as look into the mirror or look into my eyes. I can't explain the difference grammatically, perhaps another italki member can help there. If you want to hear an example, listen to " Everything I do" by Bryan Adams, it's the first line of the song.