photography question

[dakegra]

imagine the scene, if you will.

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.

Comments

[thebabynancy.livejournal.com]

I forget the actual "rule of thumb"... it may take several tries... doubling the focus sounds like it will work... but you may want to try it at 5' and 7', as well. :)

[dakegra.livejournal.com]

it's more a hypothetical 'what if?' thing. I sort of know that the person is effectively six feet away, but the image of that person is only three feet away, on the surface of the mirror.

[thebabynancy.livejournal.com]

I am fairly certain that one should double the focus... but I am not 100% sure. I am old now. And I forget. *giggle*