plastic optics

Discussion in '35mm Cameras and Accessories' started by David Lyga, May 13, 2013.

  1. David Lyga

    David Lyga Subscriber

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    Are there any examples of plastic being optically superior to glass? Have there been any serious attempts (marketed or not) to create better optics using plastic? What are the inherent obstacles towards achieving this? - David Lyga
     
  2. Two23

    Two23 Member

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    Well yes. Holga now makes their lens in Nikon mount. For $40 it's a great lens. One of the problems with plastic is it has a lot of expansion and contraction with temperature changes.


    Kent in SD
     
  3. EASmithV

    EASmithV Member

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    *cough*
     
  4. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Generally , all air to air missile lenses are acrylic. If a mach 2 speed aircraft does not escape from the view of missile , I think it is good enough. I am not good with softwares but if you can manage to use a lens design software and create your weird one element lens , you can order it from 3D printing shops with using acrylic or epoxy.

    Plastics are able to mass manufacture and require micro molds. Its a very tough problem and very expensive.

    I found a easy way to create an acrylic lens , it is cutting with lasers or water jet to make multi element non spherical cylindrical lenses.
    Its easy but designing is very difficult for me.
     
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  5. E. von Hoegh

    E. von Hoegh Member

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    Obviously some new usage of the word "great".:confused:
     
  6. erikg

    erikg Member

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    The Polaroid spectra camera has an acrylic lens that has a kidney shape as a way to shift focus quickly in a small space. it performed pretty well albeit for a Polaroid material not needing the highest resolution.
     
  7. AgX

    AgX Member

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    This seems to be a kind of near-focus-lens design, with this lens consisting of segments of different FL's which are swung into position by pivoting this lens respectively. (It's found in the Polaroid Image/Spectra cameras. I've not yet disassembled this type of camera...)
     
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  8. erikg

    erikg Member

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    This is from the camera wiki: "The Spectra range of cameras also sport better lenses on average than the 600-film range, with most of the models utilising an arc-shaped range of focusing lenses inside the body that swing across the exterior lens element to provide correct focusing, rather than adjusting the distance between internal lens elements."
    They called the lens "Quintic" it is a 3 element lens. I think this is a case that using plastic allowed a solution that may not have been possible or feasible with glass optics.
     
  9. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Polaroid uses Cooke Triplet lenses as you said it is 3 elements lens.
     
  10. Nick Merritt

    Nick Merritt Member

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    I thought that many lens designs use plastic for elements with aspherical surfaces -- much easier to mold than glass, and optically sufficient.
     
  11. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Nick,

    You are right, there is two options to make a plastic aspheric element , first mold complete lens from plastic , second taking a glass lens and adhesive a plastic aspherical attachment on to glass lens. I use only Leica and Rollei cameras and when even Nikon cant compete with Leica with glass lenses, I bet nobody cant compete with plastic lenses.

    I showed a way , if you experiment with one of designs , laser or water jet cutting or 3d printing is a way to have fun.

    Additionally , if you add nanopowders like titanium dioxide to acrylic , you can have extreme refractive indexes like 4 or so.

    But nanopowdered plastic thick products tends to crack , everyone Works on thin coatings.

    There is also , film based lenses like zoneplates or so.

    My best bet and greatest fun could be attach a plastic anamorphic attachments on to large format cameras or cine cameras or digital cine cameras. If holga sells 40 dollar lens , someone could sell to digital canon owners a anamorphic attachment.

    Umut
     
  12. cliveh

    cliveh Subscriber

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    Glass adds to the weight of a camera, which needs to be sufficiently heavy to cut down vibration.
     
  13. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    cliveh,

    You are a Leica 2 user and as you experience elmar lens is lightweight. The heavy part is brass body.
     
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  15. cliveh

    cliveh Subscriber

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    But mostly I am an M2 user and a 50mm 1.4 Summilux is not so lightweight.
     
  16. alanrockwood

    alanrockwood Member

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    One thing you might try is to download the free version of WinLens, now known as Qioptiq. With that program you can play with various design ideas. That might help you develop some insight into the design process. They also have downloads of lens libraries.
     
  17. Poisson Du Jour

    Poisson Du Jour Member

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    Quite pleasing exhibition quality wall-mounted prints (about 90cm square) have been produced from a friend's Holga. He is the manager of the lab where all my E6 and A-D printing takes place. The camera itself is rudimentary, plastic right down to its shiny lens, and rather myopic, but the images coming from it have the style that is common the PC lenses which have tilt/swing applied to restrict DoF and lateral sharpness. The lack of any fast shutter speeds also provides some opportunity to exploit dynamic movement to further accentuate the simple nature of the plastic lens. So a toy camera certainly can be used to creative effect even though it won't knock the glue off a $5,000 lens. Apples and oranges, people love the results from Holgas and Dianas; even I might be the next person to line one up on my shelf. :smile: We're not all after razor-sharp results as the so-called "holy grail" of imaging. It's occasionally quite good and satisfying to swing the other way and turn feral for a bit of fun.
     
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  18. Sirius Glass

    Sirius Glass Subscriber

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    Plastic lenses in certain uses can produce decent results. If plastic lenses were anywhere near the quality of glass lenses, the lens manufacturers would have switched over years ago.
     
  19. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    This could not be the all panorama. Every year lens designers produces new products and ordering too many molds and send to the garbage can is a enourmous Money. I watched canon factory tour and their grinding polishing machines are full automatic and extremelly fast. But may be polishing heads are costing too much Money, I dont know. And optical polymer is very expensive while BK7 is peanuts.

    In my dreams , I am seeing a 22mm LOMO Square Front Anamorphic Cine lens cut from the acrylic. Its a small television size lens and 25000 dollars used.
     
  20. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Alan , thank you.
     
  21. Newt_on_Swings

    Newt_on_Swings Member

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    The poster on that site is really cool and informative. I love info graphics, and this one has all the different types of lens surfaces and refractive indexes of materials used in common lens designs all in one place.

    http://www.winlens.de/index.php?id=14


    I would also agree that if manufacturers had found a suitable type of plastic that would match or best glass they would have all switched to it. Molding, cutting, and shaping plastic is much easier than glass. Fixing scratches is usually pretty easy with plastic as well. Anyone who has had a older watch with a acrylic crystal would know, just a little buffing will get them out, while glass needs much more abrasives and polishing time to get out a scratch.

    There a number of disposable fixed focus cameras made by Kodak, Fuji, and now Ilford that use plastic lenses which get quite good results too. If more research were done on new plastics or plastic additives maybe there might be new developments that can replace the glass used making everything lighter and cheaper. So far the latest seems to be the development of an array of micro lenses kinda like on a bugs eye, each arranged over its own sensor instead of a set of elements in a barrel, using software the information from those lenses are combined. I think the goal was to make a flatter lens array for applications such as cell phones.
     
  22. Poisson Du Jour

    Poisson Du Jour Member

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    How would aberrations be dealt with in a plastic lens?

    Glass can be ED, aspherical, apo...all manner of things and corrections. Plastic would require multiple layers, each cancelling out one problem while introducing another.
    OTOH, Cokin has shown for decades how optical quality plastic can be successfully employed as filtration, so I definitely think the process for plastic lenses is there, just not attractive as the labour- and cost-intensive process of manufacturing and refining glass, especially since most of the camera names we know of today have invested heavily in optical glass technology and refinement.
     
  23. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Newest optical poşymers still have lower abbe number than a 70 years old Leica glass and it makes they have more aberrations. Refractive indexes are lower also. There are many magic polymers out there but they are very expensive at US.

    Lens mold making is a extremelly high technology and slow process. May be material goes out of tolerances at mold quickly.

    There are hundreds of different glasses from glass manufacturers but not more than 20 with polymers , this is the problem.
     
  24. David Lyga

    David Lyga Subscriber

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    WOW, most of this is well beyond my humble brain.

    But, at least theoretically, I do get the impression that (hypothetically), optical parity could be achieved. - David Lyga
     
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  25. Peltigera

    Peltigera Member

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    Wouldn't want to go back to glass lenses in my spectacles!
     
  26. bobwysiwyg

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    +1