Here I have chosen a screen shot from British Sci-Fi TV Drama, Doctor Who. You can tell the sub genre is sci-fi because of the mysterious yellow fog against the darkness of the night, this creates a feel of suspense and of mystery for the audience (even though we know that it is only The Doctor who is going to emerge from the tardis, but the girl watching doesn't know this so the suspense we feel as the audience is from her view). The fact that it is set in the night time also reinforces the fact that it is a sci-fi drama because a stereotype is that scary things occur in the darkness of the night, also it would be harder to see any danger, and at night you can see the night sky (e.g stars, moon - more aware of outer-space). The fog also appears to be masking something, which may cause tension. If you weren't aware of Doctor Who or the tardis, the shape of the tardis in this is very unrecognizable and unusual which again may cause a feeling of mystery and tension for the audience.