I'm taking a photograph of a framed mirror, about three feet away. I want the frame in focus. I set the lens to focus at 3 feet, and take the photo. I've got a really narrow depth of field, so *only* the frame is in focus and not the background etc.
If I then want to take a photograph of *myself* reflected in the mirror, would I need to adjust the focus? Or would I need to set the focus to six feet?
I'm sure there answer should be obvious, but it's been noodling around in my head for a couple of days now, and I realised that one of you lot would be able to answer it.