Beating the diffraction limit

[dh003i]

Negative index metamaterials allows for the diffraction limit to be beaten, although a perfect image of the object still can't be reconstructed. I hope that in the years to come when this technology is introduced, large format will also receive the benefit of negative index metamaterials lenses.

Beating the diffraction limit (http://physicsworld.com/cws/article/print/19415)

(a lot of this stuff went well over my head)

[Peter K]

Negative index metamaterials allows for the diffraction limit to be beaten, although a perfect image of the object still can't be reconstructed. I hope that in the years to come when this technology is introduced, large format will also receive the benefit of negative index metamaterials lenses.
Don't believe a physicist, if one uses negative-refractive-index material as a taking lens the light will be accelerated above the speed of light and so one can get a black hole in the camera. :D

BTW every thin metal layer like used as dicroic-filter-layer has a negative refractive index too.

[Struan Gray]

Perfect lenses like this have been realised. But they work at 1:1 with a working distance of the order of the wavelength being focussed.

You might as well contact print. :-)

[A49]

There is a much simpler way to beat the "normal" diffraction limits when doing b/w: shooting with ortho- or unsensitized film or using colour filters in the direction of the blue part of the visible spectrum.

How can this work? With normal film you have for instance at f22 a diffraction limit of about 70 lines per millimeter (for shooting infinity) for panchromatic-film whose spectral-sensitivity-curve is centered at about 500 nm. When shooting ortho- or even unsensitized material, the center of the spectral-sensitivity-curve is shifted more and more in the blue direction of the spectrum. At corresponding wavelengths for instance at 486 nm you have already an increased diffraction limited resolution of 75 lpm (f22, infinity) and at 436 nm a (17 % higher than at 500 nm) value of 82 lpm (f22, infinity). I think you see where I want to go....:D

[Lynn Jones]

I getting out of here, your guys are getting too weird for me.

Lynn

[Dr Klaus Schmitt]

Don't get mad Lynn, I know you and your CV too well and you have way too much lens know how to participate here

[Nathan Potter]

There is a much simpler way to beat the "normal" diffraction limits when doing b/w: shooting with ortho- or unsensitized film or using colour filters in the direction of the blue part of the visible spectrum.

How can this work? With normal film you have for instance at f22 a diffraction limit of about 70 lines per millimeter (for shooting infinity) for panchromatic-film whose spectral-sensitivity-curve is centered at about 500 nm. When shooting ortho- or even unsensitized material, the center of the spectral-sensitivity-curve is shifted more and more in the blue direction of the spectrum. At corresponding wavelengths for instance at 486 nm you have already an increased diffraction limited resolution of 75 lpm (f22, infinity) and at 436 nm a (17 % higher than at 500 nm) value of 82 lpm (f22, infinity). I think you see where I want to go....:D

Sounds like you might want to go to eximer laser illumination at say 190 nm if you could find the glass to handle it along with a suitable emulsion. :eek:

Nate Potter, Austin TX.

[Peter Gomena]

Electron beam in a vacuum. Tough on portrait subjects, though.

Peter Gomena

[Peter K]

Electron beam in a vacuum.
Miles resp. nanometers away from the diffraction limit!

With electron lenses, only positive lenses are aviable, so one can only use very small (numerical) apertures.

[Darin Boville]

Electron beam in a vacuum. Tough on portrait subjects, though.

Peter Gomena

Great art is worth suffering for.

--Darin

[A49]

Sounds like you might want to go to eximer laser illumination at say 190 nm if you could find the glass to handle it along with a suitable emulsion. :eek:


At this time I usually shoot with ortho-materials for the reasons of their fine grain, sharpness and resultion capabilty. These emulsions are outstanding in that terms and to have a little increased diffraction limit on the blue side of the spectrum is a nice side effect. Sometimes, if I was lucky and everything during shooting worked well, my pictures are very sharp... :) I admit I am from time to time obsessed with sharpness and resolution and going beyond the limits. But shooting on holographic emulsions or using laser to illuminate is even too far out for me. ;)

[dh003i]

I thought the diffraction limit was an aerial property of the maximum resolution of the lens, determined by the interaction of the light with the diaphragm? I use some Kodak Aerographic Pan X II film that gets 400 - 500 lp/mm (if you have a lens that can resolve that). The resolving power of the film is what it is, independent of the diffraction limit, right? Then final resolution is approximately 1/(1/Ra + 1/Rf)? (yea, I know, MTF is the right way to do it).

[Peter K]

I thought the diffraction limit was an aerial property of the maximum resolution of the lens, determined by the interaction of the light with the diaphragm?
That's the definition I know too. Also "sharpness" is a physiological term not an optical.

[Brian Stein]

In the article they are using ~1GHz radiation. If my maths is ok this is about 300 mm wavelength. They may be beating the diffraction limit, but they arent going to be making any sharp optical images soon!

[Sirius Glass]

One could get rid of the diffraction with the use of Photo$hop and a flux capacitor but then it would not be photography.

Steve

[aduncanson]

I thought the diffraction limit was an aerial property of the maximum resolution of the lens, determined by the interaction of the light with the diaphragm?

Okay, I have been struggling for some time with just how to say this.

DIFFRACTION HAS ALMOST* NOTHING TO DO WITH THE INTERACTION OF LIGHT WITH THE DIAPHRAGM!!!

Rather diffraction occurs because the aperture, that is the hole from which the wavefront emanates, IS NOT INFINITE! If you had a perfect infinite wavefront forming a perfect image and God, Herself, intervened to take away the light waves coming from outside of some circumscribed aperture, then you would see essentially* the same diffraction in the image as comes from a using a physical diaphragm. The cause of the diffraction is the lack of those contributions from the light waves that would have come from outside of the aperture.

I don't know why correcting this misunderstanding is so important to me, but evidently it is. I feel better now.

*Yes the shape of the edge, or the thickness of the diaphragm, would produce some higher order (read, negligible) effects on the diffraction.

[A49]

I thought the diffraction limit was an aerial property of the maximum resolution of the lens, determined by the interaction of the light with the diaphragm?

Yes I also think so. And the diffraction limit depends on the wavelength or the wavelengths of the spectrum of light that reaches the aperture or can be recorded by the film. The shorter the wavelengths the higher the diffraction limit (within a reasonable range - the range in which photography works).

Andreas

[Peter K]

Yes I also think so. And the diffraction limit depends on the wavelength or the wavelengths of the spectrum of light that reaches the aperture or can be recorded by the film. The shorter the wavelengths the higher the diffraction limit (within a reasonable range - the range in which photography works).
That's true only with "diffraction limitet lenses".

With any other lens lens-faults like chromatical aberrations, spherical aberration, astigmatism, coma etc. etc. have much more influence in limiting resolution as a change in the wavelenght.

[John Schneider]

Don't believe a physicist, if one uses negative-refractive-index material as a taking lens the light will be accelerated above the speed of light and so one can get a black hole in the camera. :D

Okay, so use a tachyon-emitting "light source" and everything will be fine again ;) .