Quote Originally Posted by archphoto View Post
You are measuring though the extension tubes and the lens, if the lens is stopped down the camera will show you what shutterspeed you need for a correct exposure, it is that simple.
On Auto the camera will choose the correct shutterspeed, no calculations or corrections needed as long as your object has a general density, so not (pure) white or (pure) black.

Peter

Peter and nsurit,

Thank you both for responding.

OK, I'm reassured and have been taking a few shots: seems just too easy!

I'll let you know how I got on, when the prints come back (still a few left to go on the roll).