but seriously, i am a size fourteen. it’s a bitch to get shoes.
Are you really Prismo2?
I think the thrust of the question was more about the scale on which the reflective material of a mirror would stop functioning as a mirror and become visible itself, not so much about whether a camera could, in reality, resolve such an occurrence.
The shiny stuff on most mirrors is a thin layer of a pure metal or an alloy, applied to the back of the glass. As such, I would guess that the agents of the reflection are the valence electrons of the metal (since the outer electrons in a metal are well-shielded from the nucleus, they are easy to ionize, and also easy to excite into higher states, which is how reflection happens – the electrons get excited by the incoming light, then re-emit the light as they fall back to their original states.) So no noticeable breakdown in reflectivity would be noticeable down to the atomic level, which is well below what can be observed optically, or even with an electron microscope.
So I’m pretty sure that, as far any light-microscope could zoom in, the reflective quality of the mirror would remain.
**no noticeable breakdown in reflectivity would be noticeable… even with an electron microscope. **
wow oh wow! so does this mean that if i scanned a really high-quality (like what the hubble shoulda been, or one of them giant pools of mercury mirrors) mirror with an electron microscope, it would only be getting images of the reflectee?
or i gather that since an electron microscope uses electrons and not light, we should be talking about a great electron-reflecting material or surface. but i don’t know any.
PaulT:
If your interpretation is correct, then you needn’t worry about seeing the individual molecules of the mirror.
You are never focusing ON THE MIRROR ITSELF. When you bank your line of sight off the mirror it is “folding” that line of vision. The mirror does not act like a movie screen on which the image is projected.
Since you’re never trying to focus on the mirror plane itself (unless your object is very close to the mirror) the size of the individual atoms becomes pretty much irrelevant. What is important is the quality of the wavefront that gets reflected from the mirror. If the mirror is not perfectly flat it will inevitably distort the image. This is very comon – you pays lotsa money to manufactrers of optical surfaces to produce really flat mirrors. If you want to see a bad mirror, take your averahe handmirror and step WAYYY back, and you can see the distortions. Window glass looks pretty flat, but if you look at sunlight reflected from a window you can usually see the effects of bulges. Or look at the side of a building covered with mirrored glass – the reflection is never perfect.
Incidentally, since you are not focussing on the mirror itself, this explains why you do not want to use an autofocus with such a mirror shot – the camera will focus on the mirror plane, instead of on the real object you wanted to photograph, and you’ll end up with a blurry picture.
That’s true, Cal, focus is totally separate issue.
So jb, if you were to do that with the electron microscope I’m not sure what you’d get, because I’m not sure if it’s even possible for a material to be ‘reflective’ of electrons – they’re not like photons, to be created or absorbed at will – but if you did it with the world’s best optical microscope you’d just get a REALLY blurry picture of the reflection.