Holographically Correction

Discussion in 'Camera Building, Repairs & Modification' started by Mustafa Umut Sarac, Aug 23, 2012.

  1. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Holographically correction is widely use to cancel of aberrations of primary mirror of space telescopes. There is even correction of aberration of flowing hot cold layers of air of atmosphere where the telescope looks through.

    Its not an new process and looks basic.

    You send a laser beam to the mirror , mirror focus it on to film which is enlighted with other laser also. Two laser beams form an hologram. You develop this hologram , put to the path of light and voila , other image will be free from all aberrations.

    With mass productibility of holograms could make it use at all of our cameras.

    I am thinking to buy fluro film , strech to the frame ,put acrlic on it , inflate from the bottom and form a male mirror and produce
    5 foot wide primary mirrors. Problem is the streching of the polymers but if you built a huge telescope , you know how to figure it out to holographically correct.

    My interest is to put one of this in to any pinhole camera may be I thought it would be possible for others also.

    Lets put it for 4x5.

    Send a beam from front of camera to the lens and send other one to the back of 4x5 film at holder. Develop your film and your hologram is ready. Next time , put a film back of hologram and all aberrations is gone.

    My question , how to cover entire film with these two tiny lasers ?

    And what might be the distance of first laser to lens ?

    Umut
     
  2. Jesper

    Jesper Subscriber

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    First of all you need a single laser that you divide into two beams (to produce a hologram you need coherent light) this ca be done with a semi-transparant mirror.
    To spread the light you diffract it through a tiny hole (a pinhole for us photogs) and you do that with both beams. The placement of the pinholes depends on the area that you need to cover with light.

    In order to produce an image you let one diffracted beam reflect of the object and then onto the plate while the other diffracted beam goes directly to the plate. The diffraction image on the plate can now be used to reproduce the light coming from any of the light sources when hit by light from the other. Hitting the plate with the laser beam that didn't reflect on the object will create the image of the object (and the other way around if you ever mange that setup).

    The problem with holograms and photographic material is that they are not consistent enough to to used. The plastic base is not solid not to mention that the emulsion moves with humidity (remember that a shift of half the wavelength will, cancel the image). For this reason holograms are not made on photographic emulsions but special emulsions on glass plates (and they still shift a little in colour).
    The kind of holograms that you see on credit cards etc are pressed and not recorded and that is another story (still they need a stable base so they are done on metal)
     
  3. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Thank you Jasper.

    Thank you reminding me how a real hologram was made , how laser beam spread and great information on holographic emulsions.

    You can, if you accept , write a paragraph how emboss was made , can cnc machines do that or another photopolymer trick?

    I will write more , I just stopped a fire in electric vacuumer , never vacuum a burning cigarette :smile:

    Umut
     
  4. Steve Smith

    Steve Smith Subscriber

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    The answer is in your second dilemma. Vacuum forming!


    Steve.
     
  5. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    We bought a Fakir vacuumer. Fakir is means poor guy and my Fakir is in poor condition. I have to find replacement parts.

    The good thing about inflated mirrors , your f factor is faraway lower than the hand grinding so you can put the secondory mirror only far from the primary , 1 meter distance. But I dont know is that about shallower curvature or deeper curvature.
    And I dont know what would be the magnification.

    My inflating technology comes from 1960,70s Hippie Buildings , they called them domes , Mr.Bini from Italy was pioneer of that method , they lay a flexible plastic to the ground , cover it with centered star shaped steel flexible rods where rod ends connected to springs and pour concrete to top of two layers , when you inflate the film with less pressure than smoking , it elevates and in 2 days concrete pass the first stage of set and you remove the plastic.

    There were lots of buildings at Australia made with that way and tens of extreme big silos at Pakistan.

    Hippies like the idea and they built many small residents out of them , some made concrete yachts and traveled the world , you know.

    http://www.binisystems.com/

    binishell.jpg
     
  6. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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