Enchanted Katya and the Mystery of the Lost Wizard Juegos Descargas

Hi Andrew and Clay,The points raiesd are valid. One of the problems in understanding things like this is that for 95% (and more) of photographers the acquired knowledge of optics is based entirely on what lenses, prisms and such hardware do to light beams. There is precious little of this stuff left in advanced level courses (too hard it hurts a bit) but at university level you do no geometrical optics' at all the part of the study that embraces lenses unless, that is, you take a special (rather turgid) module.I did my undergraduate physics 40 years ago and things have changed a bit but not the basic principles. Even then, I only studied wave optics which had to do with wave equations and diffraction the lens equations and programming I picked up later as a post grad.What I am getting at is that our association as photographers with lenses etc gives a limited picture of what is going on. Amazingly, all the information in the light leaving a subject is contained at every point in the wavefront as the light wave spreads out. The wavefront is the surface perpendicular to the direction in which the wave travels think of it as an expanding sphere a balloon spreading outwards at the speed of light. Over that spherical surface is a complex morass of electric and magnetic fields varying rapidly. You may have come across the idea that each point on a hologram has all the information from the wavefront just the more points to work from the better that info can be extracted.When light leaves a point' on a subject it spreads out: a lens gathers the information and we think of it creating an image by bringing light from each point on an object to its own corresponding point in the image plane (on a film or sensor) these are not really points they are tiny Fresnel diffraction patterns but no matter the idea works.One way of looking at the lens is as a device that sorts out the information on the wavefront that hits it. It effects what is called a Fourier transform albeit a very complicated one to do this. The result is that image points' are recreated from this info from the chaos of the wavefront. The lens image is 2 dimensional on a sensor whereas that information in the wavefront is, in effect from a 3D object. So, already a lot has been lost.You might want to ask a question about the information in that wavefront and say well what did it come from what did the object look like. There is a whole process called Inverse Fourier Transformation that lets you go backwards by solving mathematical equations. They are individually pretty standard (but messy) differential equations in three-dimensions that are the stuff of University level applied maths. If you have a moving subject you will need to include time a fourth dimension. The problem is that there are millions, even billions of them to solve and that requires the blistering speed of modern microprocessors it is the sort of thing that Photoshop does every time you apply a sharpening algorithm or the like. The steps are obviously different but the idea of doing something repetitively millions of times is the same. The algorithm is the recipe applied again and again to allow thisI must admit when, decades ago, I worked with such things the idea of all the info being at every point on a hologram plate was utterly alien. To capture that info involved shining one laser beam on the subject and letting the reflected beam interact with another to produce a series of interference patterns captured on a film plate placed strategically in the path. The picture' could be unlocked by shining another laser on it a hologram seems 3D because it appears to allow you to see behind' in a normal photograph the lens does not recreate that, though the info is there, in the wavefrontMy apologies to anyone to whom this explanation seems naive but I think/hope that I have not stretched the principles too much.What I wanted to convey was that it has been known for a long time that a wavefront has all this information but extracting it in a practical sense was seemingly impossible. The achievement is incredible and will revolutionise photography I have no doubt.Changing focus turning blurs into sharp' points:If you can use the inverse transform to tell you what point some information came from and you get a blur' then you can push things further back and ask what sharp point it came from.Paul