# Converging mirrors and the transition between inverted and non-inverted images

I was talking with a friend recently about concave mirrors, which frequently invert the reflected image - I think we were playing with a spoon. I raised the question, if you had a mirror whose shape could be easily controlled so you could move it from convex through being flat to being concave, at what point does the image flip from being the right way up to being inverted - is there some sort of discontinuity? If not how would this transition occur?

• Thanks. But what exactly would the transition look like as I approach the d=f from either side? This seems to be the 'discontinuity' point so what would I see as I travel from d=f-δ to d=f+δ? – Mr. Boy May 8 '14 at 8:33