Very nice information indeed Alcheringa.
It was only few months ago I found out about the possibility of making a DIY anamorphic lens,it was a big surprise that an aparatus which costs too much for me to buy can be built with little work and under 100Euros/Dollars.
I have not yet watched any movie or changed the projectors settings with my new DIY lense,so I can't say too mutch about the result yet,but I believe the result may not be as good as with the factory made optically corrected solid prism like lences as Prismasonic or Panamorph.
It is very nice to know there are other and maybe better solutions in making a DIY lens, as the posibility of buying one (new) is not an option for me.
If you have more information or good links to share I would be grateful .
It was only few months ago I found out about the possibility of making a DIY anamorphic lens,it was a big surprise that an aparatus which costs too much for me to buy can be built with little work and under 100Euros/Dollars.
I have not yet watched any movie or changed the projectors settings with my new DIY lense,so I can't say too mutch about the result yet,but I believe the result may not be as good as with the factory made optically corrected solid prism like lences as Prismasonic or Panamorph.
It is very nice to know there are other and maybe better solutions in making a DIY lens, as the posibility of buying one (new) is not an option for me.
If you have more information or good links to share I would be grateful .
DYI Anamorphic lens
Thank you Tor for starting this long, but extremely informative thread.
I am new to this forum and I am using a 16:9 projector that I have tested with a commercial 1.78:1 anamorphic lens. Although it is short throw it works, but, due the cost of the lens, I won't be buying one anytime soon. I am wanting to add the anamorphic lens to my HT to allow me to view all anamorphic program at the same height. I have read all 39 pages, and am very interested in this thread but still have some questions for those in the know…
I did purchase a used 16mm “Prominar Anamorphic 16-H 54221” but as it is a 2:1 stretch lens, it is not suitable for video applications. The lens could be used to compress the image if turned 90 degrees, but as I said, is not suitable for video, not without severe alteration from a scaler…
When I tried the commercial 1,78:1 version, I found-
1. With the DVD player set to 16:9 (anamorphic enhanced disc) and by using either a 4 x 3 projector or using my 16:9 in 4 x 3 mode, that the image was expanded to display a geometry correct image of approx 1.78:1.
2. I then chose a DVD that is 2.35:1 and repeated the process. The image worked the same as if I was using the 16:9 mode without the lens, geometry correct, but with black bars top and bottom. I then switched from the 4 x 3 mode to the 4 x 3 ZOOM mode and this elimated the black bars at the top and bottom. What I got was a very much closer representation to an actual cinema scope presentation, with all pixels used and no black bars and correct geometry. I was very impressed…
I apologize if I missed any answers to the questions I am about to post…
16:9 native projectors. How many others use 16:9 projectors and want 21:9 images at the same height?
Solid prisms. There has been mention of the use of solid prisms made from either glass or from acrylic. What were the results of solid prisms?
Expanding lens. I know it goes on it’s side to become an expanding lens, but why does it have to be turned around?
Barrel distortion. When I played with the commercial lens, I got barrel distortions. I was told that I could eliminate this by curving the screen. Tor has mentioned this too. Has anyone tried making a curved screen?
Angles. So far it seem that the two angles needed are 30 and 24 degrees. Any change there, and what happens with two 30 or 24s?
Mark
Thank you Tor for starting this long, but extremely informative thread.
I am new to this forum and I am using a 16:9 projector that I have tested with a commercial 1.78:1 anamorphic lens. Although it is short throw it works, but, due the cost of the lens, I won't be buying one anytime soon. I am wanting to add the anamorphic lens to my HT to allow me to view all anamorphic program at the same height. I have read all 39 pages, and am very interested in this thread but still have some questions for those in the know…
I did purchase a used 16mm “Prominar Anamorphic 16-H 54221” but as it is a 2:1 stretch lens, it is not suitable for video applications. The lens could be used to compress the image if turned 90 degrees, but as I said, is not suitable for video, not without severe alteration from a scaler…
When I tried the commercial 1,78:1 version, I found-
1. With the DVD player set to 16:9 (anamorphic enhanced disc) and by using either a 4 x 3 projector or using my 16:9 in 4 x 3 mode, that the image was expanded to display a geometry correct image of approx 1.78:1.
2. I then chose a DVD that is 2.35:1 and repeated the process. The image worked the same as if I was using the 16:9 mode without the lens, geometry correct, but with black bars top and bottom. I then switched from the 4 x 3 mode to the 4 x 3 ZOOM mode and this elimated the black bars at the top and bottom. What I got was a very much closer representation to an actual cinema scope presentation, with all pixels used and no black bars and correct geometry. I was very impressed…
I apologize if I missed any answers to the questions I am about to post…
16:9 native projectors. How many others use 16:9 projectors and want 21:9 images at the same height?
Solid prisms. There has been mention of the use of solid prisms made from either glass or from acrylic. What were the results of solid prisms?
Expanding lens. I know it goes on it’s side to become an expanding lens, but why does it have to be turned around?
Barrel distortion. When I played with the commercial lens, I got barrel distortions. I was told that I could eliminate this by curving the screen. Tor has mentioned this too. Has anyone tried making a curved screen?
Angles. So far it seem that the two angles needed are 30 and 24 degrees. Any change there, and what happens with two 30 or 24s?
Mark
16:9 native projectors. How many others use 16:9 projectors and want 21:9 images at the same height?
I do. I use a Panasonic AE-700 with a 1.33:1 cylindrical stretch anamorphic lens of my own design (3 anti-reflection coated elements, two types of glass: the end elements for the stretch and the middle element for focus correction). The AE-700 has a mode, ZOOM-1, which vertically stretches a 16x9 image. With 21:9 images this neatly eliminates the letterbox black bars. The anamorphic lens then stretches this back to normal geometry, but at full height, using all 1280x720 pixels of the projector's LCD imaging chips. The result is very smooth, very bright (about 30% brighter than without an anamorphic lens).
Expanding lens. I know it goes on it’s side to become an expanding lens, but why does it have to be turned around?
There are two types of anamorphic adapter: compression and expansion. At a very basic level to make a compression adapter from an expansion adapter you just flip the expansion adapter longitudinally (i.e. you reverse it lengthways).
However, there are problems with this crude approach. Usually the output lens (lens nearest the screen) of an expansion system is quite a bit larger than the input lens, because it has to deal with a wider beam as the beam expands through the adapter due to distance from the projector, plus of course the anamorphic effect. Flipping the adapter longitudinally will place the large diameter lens nearest the projector and the small lens nearest the screen. This is exactly what you don't want! You will get vignetting of the projected image as the beam is cropped by the (now) small output lens. The vignetting problem applies to both prismatic and cylindrical adapters.
Additionally, with cylindrical adapters, not only do you have to flip the whole adapter, but you also have to flip the individual elements as well, to restore optical performance. Prismatic adapters are theoretically bi-directional (if the prism size issue can be overcome), but cylindrical adapters have both size and optical problems.
The advantage of cylindrical versus prismatic adapters is size. Cylindricals can be made much smaller than prismatics and can be tailored for very short throws. Prismatics have planar sides and that's it... very little room for improvement of the performance for HT purposes.
This is the answer to your question about "turning around" the lens.
Rotating a lens 90 degrees ("putting it on it's side") does not turn a compression adapter into an expansion adapter (or vice versa). It merely changes the direction of compression or expansion from vertical to horizontal in the case of a compression adapter, or from horizontal to vertical, in the case of an expansion adapter.
With my expansion adapter, I turn the lens 90 degrees to watch 4x3 "classic" format movies. First I digitally expand the 4x3 movie to 16x9 (leaving everyone in the movie "short and fat", but using all the pixels of the imaging LCDs) and then the anamorphic expander (at 90 degrees) expands this vertically so that geometry is restored. The image is now too tall to fit my screen so I zoom back a bit to reduce the height back to "normal". The images are stunning - once again bright and smooth - and there are no letterbox bars at the sides.
Barrel distortion. When I played with the commercial lens, I got barrel distortions. I was told that I could eliminate this by curving the screen. Tor has mentioned this too. Has anyone tried making a curved screen?
Compression adapters barrel distort. Expansion adapters pincushion distort. In my case I use an expansion adapter, so I will talk about its pincushion distortion. The problems between pincushion and barrel distortion are similar in nature, having to do with the short throw, wide beam typical of HT.
The wider the beam the more you will get pincushion or barrel distortion (depending on your adapter type). Since HT typically has short throw, wide beams, the compression theatrical adapter you're experimenting with exhibits barrel distortion. The only way around this is to use longer focal length elements in your adapter. The trade off is that with longer focal length elements the whole adapter becomes longer. Longer means bigger in diameter, as the beam has more length to expand. You end up with huge elements, up to 200mm across in some cases. Very heavy also.
My own elements are 70mm and 90mm (100mm in length), biggish, but still quite manageable: a nice combination of weight and size versus utility. I have some pincushion distortion if my lens is not orthogonal to the screen (i.e. at right angles i both directions), but otherwise it seems pretty good in that regard, if it is straight-on to the screen.
Anamorphic adapters are not as sophisticated as projection lenses. This means that if you are using lens shift (quite common nowadays) to center your image on-screen, the adapter will not fully pass the image without some keystoning. If you're using your projector off-centre you just have to put up with this. I get around it by matting my 21:9 image. The right-hand side of my image is about 1 inch bigger - vertically and horizontally - than the left hand side, across a 120 inch screen, less than 1 per cent distortion. The matting makes this discrepancy disappear by literally hiding it. Longer focal length elements would fix the problem (or reduce it) but I haven't bothered, as increasing the adapters length and diameter would make it too heavy and would obscure the IR receivers on both projector and DVD player. Being a couch potato, I wouldn't like this.
Angles. So far it seem that the two angles needed are 30 and 24 degrees. Any change there, and what happens with two 30 or 24s?
I never made a prismatic adapter as I'm hopeless with hobby-type craft work and would have just ended up flooding my home (as many others have).
The angles (and different filling liquids) are supposed to compensate for color aberrations. Maybe they do. But this fluid-filled home-made adapter, although it seems easy and cheap, will give you big problems with reflections and light loss if you don't have the glass properly anti-relfection coated ("anti-reflection" picture framing glass will not, repeat NOT, work). I have a Panavision prismatic system (the original design from 1951) that I bought off ebay, and its prisms are AR coated, as well as being achromatic doublets, and there's still quite a lot of reflection and light loss, especially at wide beam angles (also pincushion distortion). And there's also a weight problem: just the glass alone weights 9 pounds!!!
So, if you're going to go ahead and make your own prismatic adapter, use the angles and materials suggested, as these have been found empirically to work OK.
Conclusion
Re-reading the above I sound like a bit of a grinch, full of caveats and negativity. But I'm not. I love watching films with an anamorphic adapter. I even watch 16:9 format films this way as they can usually be cropped to fit my 21:9 screen. They take on a whole new dimension. My images are bright and clear and definitely have the "wow" factor.
But you have to be careful to pay attention to the details or, after the initial "wow" has worn off, all you'll see are the color aberrations or the distortion or the reduced brightness that will occur if you don't do it right first time. This is what happened with my first couple of cylindrical prototypes (my first one used lenses from an optometrist, and I thought it was wonderful, but now I can't watch films through it, they look so awful compared to my latest version, which has elements made in China at a hi-tech optics factory).
Some of the greatest and most commercially successful optical designers in history (Panavision, Arriflex etc.) have put their minds to anamorphic adapter design. In other words, it looks easy, but it isn't.
Hope some of this helps to temper your enthusiastic expectations with sober reality.
I do. I use a Panasonic AE-700 with a 1.33:1 cylindrical stretch anamorphic lens of my own design (3 anti-reflection coated elements, two types of glass: the end elements for the stretch and the middle element for focus correction). The AE-700 has a mode, ZOOM-1, which vertically stretches a 16x9 image. With 21:9 images this neatly eliminates the letterbox black bars. The anamorphic lens then stretches this back to normal geometry, but at full height, using all 1280x720 pixels of the projector's LCD imaging chips. The result is very smooth, very bright (about 30% brighter than without an anamorphic lens).
Expanding lens. I know it goes on it’s side to become an expanding lens, but why does it have to be turned around?
There are two types of anamorphic adapter: compression and expansion. At a very basic level to make a compression adapter from an expansion adapter you just flip the expansion adapter longitudinally (i.e. you reverse it lengthways).
However, there are problems with this crude approach. Usually the output lens (lens nearest the screen) of an expansion system is quite a bit larger than the input lens, because it has to deal with a wider beam as the beam expands through the adapter due to distance from the projector, plus of course the anamorphic effect. Flipping the adapter longitudinally will place the large diameter lens nearest the projector and the small lens nearest the screen. This is exactly what you don't want! You will get vignetting of the projected image as the beam is cropped by the (now) small output lens. The vignetting problem applies to both prismatic and cylindrical adapters.
Additionally, with cylindrical adapters, not only do you have to flip the whole adapter, but you also have to flip the individual elements as well, to restore optical performance. Prismatic adapters are theoretically bi-directional (if the prism size issue can be overcome), but cylindrical adapters have both size and optical problems.
The advantage of cylindrical versus prismatic adapters is size. Cylindricals can be made much smaller than prismatics and can be tailored for very short throws. Prismatics have planar sides and that's it... very little room for improvement of the performance for HT purposes.
This is the answer to your question about "turning around" the lens.
Rotating a lens 90 degrees ("putting it on it's side") does not turn a compression adapter into an expansion adapter (or vice versa). It merely changes the direction of compression or expansion from vertical to horizontal in the case of a compression adapter, or from horizontal to vertical, in the case of an expansion adapter.
With my expansion adapter, I turn the lens 90 degrees to watch 4x3 "classic" format movies. First I digitally expand the 4x3 movie to 16x9 (leaving everyone in the movie "short and fat", but using all the pixels of the imaging LCDs) and then the anamorphic expander (at 90 degrees) expands this vertically so that geometry is restored. The image is now too tall to fit my screen so I zoom back a bit to reduce the height back to "normal". The images are stunning - once again bright and smooth - and there are no letterbox bars at the sides.
Barrel distortion. When I played with the commercial lens, I got barrel distortions. I was told that I could eliminate this by curving the screen. Tor has mentioned this too. Has anyone tried making a curved screen?
Compression adapters barrel distort. Expansion adapters pincushion distort. In my case I use an expansion adapter, so I will talk about its pincushion distortion. The problems between pincushion and barrel distortion are similar in nature, having to do with the short throw, wide beam typical of HT.
The wider the beam the more you will get pincushion or barrel distortion (depending on your adapter type). Since HT typically has short throw, wide beams, the compression theatrical adapter you're experimenting with exhibits barrel distortion. The only way around this is to use longer focal length elements in your adapter. The trade off is that with longer focal length elements the whole adapter becomes longer. Longer means bigger in diameter, as the beam has more length to expand. You end up with huge elements, up to 200mm across in some cases. Very heavy also.
My own elements are 70mm and 90mm (100mm in length), biggish, but still quite manageable: a nice combination of weight and size versus utility. I have some pincushion distortion if my lens is not orthogonal to the screen (i.e. at right angles i both directions), but otherwise it seems pretty good in that regard, if it is straight-on to the screen.
Anamorphic adapters are not as sophisticated as projection lenses. This means that if you are using lens shift (quite common nowadays) to center your image on-screen, the adapter will not fully pass the image without some keystoning. If you're using your projector off-centre you just have to put up with this. I get around it by matting my 21:9 image. The right-hand side of my image is about 1 inch bigger - vertically and horizontally - than the left hand side, across a 120 inch screen, less than 1 per cent distortion. The matting makes this discrepancy disappear by literally hiding it. Longer focal length elements would fix the problem (or reduce it) but I haven't bothered, as increasing the adapters length and diameter would make it too heavy and would obscure the IR receivers on both projector and DVD player. Being a couch potato, I wouldn't like this.
Angles. So far it seem that the two angles needed are 30 and 24 degrees. Any change there, and what happens with two 30 or 24s?
I never made a prismatic adapter as I'm hopeless with hobby-type craft work and would have just ended up flooding my home (as many others have).
The angles (and different filling liquids) are supposed to compensate for color aberrations. Maybe they do. But this fluid-filled home-made adapter, although it seems easy and cheap, will give you big problems with reflections and light loss if you don't have the glass properly anti-relfection coated ("anti-reflection" picture framing glass will not, repeat NOT, work). I have a Panavision prismatic system (the original design from 1951) that I bought off ebay, and its prisms are AR coated, as well as being achromatic doublets, and there's still quite a lot of reflection and light loss, especially at wide beam angles (also pincushion distortion). And there's also a weight problem: just the glass alone weights 9 pounds!!!
So, if you're going to go ahead and make your own prismatic adapter, use the angles and materials suggested, as these have been found empirically to work OK.
Conclusion
Re-reading the above I sound like a bit of a grinch, full of caveats and negativity. But I'm not. I love watching films with an anamorphic adapter. I even watch 16:9 format films this way as they can usually be cropped to fit my 21:9 screen. They take on a whole new dimension. My images are bright and clear and definitely have the "wow" factor.
But you have to be careful to pay attention to the details or, after the initial "wow" has worn off, all you'll see are the color aberrations or the distortion or the reduced brightness that will occur if you don't do it right first time. This is what happened with my first couple of cylindrical prototypes (my first one used lenses from an optometrist, and I thought it was wonderful, but now I can't watch films through it, they look so awful compared to my latest version, which has elements made in China at a hi-tech optics factory).
Some of the greatest and most commercially successful optical designers in history (Panavision, Arriflex etc.) have put their minds to anamorphic adapter design. In other words, it looks easy, but it isn't.
Hope some of this helps to temper your enthusiastic expectations with sober reality.
Thank you Alcheringa for your prompt response.
I am very impressed with the Prismasonic that was posted by Hezz back at post 374.
This is more to what I want to thry and build. It appears that both prisims are the solid glass and a local plastics company said they might be able to laser cut prisms out of acrylic me. I like the abilty to adjust each prism. So far the quoted prices are very reasonable...
Mark
I am very impressed with the Prismasonic that was posted by Hezz back at post 374.
This is more to what I want to thry and build. It appears that both prisims are the solid glass and a local plastics company said they might be able to laser cut prisms out of acrylic me. I like the abilty to adjust each prism. So far the quoted prices are very reasonable...
Mark
Laser cutting (or any cutting) of prisms won't work, especially if done at an "industrial" perspex or acrylic cutting factory.
The slightest imperfection will render the adapter useless... and there WILL be imperfections, many of them. "Flaming" the acrylic won't help. This is not an "optics quality" finish. You would have to polish the cut prisms on an optical bench to get any sort of even quarter-way performance out of them.
There go the DIY savings!
I'm sounding negative again, but in this case the advice will save you a lot of time on a wasted effort.
The liquid-filled glass idea is best for DIY, due to the inherent smoothness of the glass and clarity of the liquids, but it has its limitations too as this thread attests.
The slightest imperfection will render the adapter useless... and there WILL be imperfections, many of them. "Flaming" the acrylic won't help. This is not an "optics quality" finish. You would have to polish the cut prisms on an optical bench to get any sort of even quarter-way performance out of them.
There go the DIY savings!
I'm sounding negative again, but in this case the advice will save you a lot of time on a wasted effort.
The liquid-filled glass idea is best for DIY, due to the inherent smoothness of the glass and clarity of the liquids, but it has its limitations too as this thread attests.
Thanks for head up 🙂
I understand exactly what will happen if the surfaces are not 100%.
If I adopt the liquid filled prism concept, I did read that someone used thin lexon (which did not glue perfectly flat) so what about thicker lexon, say in the order of 10mm. The plastic manufacture said that he can cut and glue with a special bonding agent that should make a water tight seal. He also said that he can drill and tap the top to allow the installation/removal of a threaded bung. We also discussed adding a peice to the top (one side, as my prizms are to be used horizontally as an expanding lens) to form a small chamber for the expansion of the liquid.
Reading over the posts, a terpentine oil was used for one prism, water for the other. One member has suggested the terpintine oil can be used for both.
Is this terpintine oil the same as the commonly available terpintine?
Does terps damage lexon, and if so, what about using a metholated spirits? Has anyone tried that?
Sorry if any of these questions are repetitive, but I am really keen now to build something that will allow me to use the full width of the curved screen I have recently build...
Mark
I understand exactly what will happen if the surfaces are not 100%.
If I adopt the liquid filled prism concept, I did read that someone used thin lexon (which did not glue perfectly flat) so what about thicker lexon, say in the order of 10mm. The plastic manufacture said that he can cut and glue with a special bonding agent that should make a water tight seal. He also said that he can drill and tap the top to allow the installation/removal of a threaded bung. We also discussed adding a peice to the top (one side, as my prizms are to be used horizontally as an expanding lens) to form a small chamber for the expansion of the liquid.
Reading over the posts, a terpentine oil was used for one prism, water for the other. One member has suggested the terpintine oil can be used for both.
Is this terpintine oil the same as the commonly available terpintine?
Does terps damage lexon, and if so, what about using a metholated spirits? Has anyone tried that?
Sorry if any of these questions are repetitive, but I am really keen now to build something that will allow me to use the full width of the curved screen I have recently build...
Mark
If I have understood correctly the best results are obtained with clyserine filled prisms.
I made one with antireflection glass and clyserine filled prisms some time ago.The main reason for making the lens was my entry level LCD projector with 854x480 pixels and plenty of screendoor.The lens really makes wonders to the picture,I watch at 1.4x screen width at the picture projected by this sheep combo of DIY lens and the not so perfect projector.
Some time ago I tested how is the picture without the lens and was really surprised at the amount of the digital artifacts in the picture.
The picture is distorted by some barrel distortion,it was possible to adjust the lens so that the bottom side of it is straight,this way it is nicer to read the substitutes.Not sure but seems like the contrast ratio went down as well,it was needed to up the colour level. The lens is reflecting a dim second picture to my white ceiling,this could be avoided by making a small lid in front the lens,I suppose there goes the extra brightnes gained by the use of full resolution in 2.35:1 movies.
The lens is not really so difficult to make,it took surprising amount of time thought.......and the big question ,did it LEAK?
Oh yeah it did,the pvc material and silicone I used at first didn't colaborate very well
silly me....
It was worth it, the 100$ was well spent.Hopefully my next projector will be of higher level and less screen door,do not know if this lens can be used to improve the picture then ,but so far so good 🙂
I made one with antireflection glass and clyserine filled prisms some time ago.The main reason for making the lens was my entry level LCD projector with 854x480 pixels and plenty of screendoor.The lens really makes wonders to the picture,I watch at 1.4x screen width at the picture projected by this sheep combo of DIY lens and the not so perfect projector.
Some time ago I tested how is the picture without the lens and was really surprised at the amount of the digital artifacts in the picture.
The picture is distorted by some barrel distortion,it was possible to adjust the lens so that the bottom side of it is straight,this way it is nicer to read the substitutes.Not sure but seems like the contrast ratio went down as well,it was needed to up the colour level. The lens is reflecting a dim second picture to my white ceiling,this could be avoided by making a small lid in front the lens,I suppose there goes the extra brightnes gained by the use of full resolution in 2.35:1 movies.
The lens is not really so difficult to make,it took surprising amount of time thought.......and the big question ,did it LEAK?
Oh yeah it did,the pvc material and silicone I used at first didn't colaborate very well
silly me....It was worth it, the 100$ was well spent.Hopefully my next projector will be of higher level and less screen door,do not know if this lens can be used to improve the picture then ,but so far so good 🙂
to edit my post above:
When talking about the prism type of lenses the glyserine is good liquid to use,it is not flammable as spirits and it is "thicker" so it will not leak so easily 😉 I think the liquid used in some Panamorph models is similar to glyserine?
I have not tested the picture quality between different liquids.
p.s. by "substitutes" I mean subtitles
When talking about the prism type of lenses the glyserine is good liquid to use,it is not flammable as spirits and it is "thicker" so it will not leak so easily 😉 I think the liquid used in some Panamorph models is similar to glyserine?
I have not tested the picture quality between different liquids.
p.s. by "substitutes" I mean subtitles
I have build a jig for the plastics engineer to make my prisms out of 6mm perspex.
I obtained a spec sheet for substances that do not re-act with perspex. All the fluids are listed with either a + (Yes), a - (No) or a 0 (Ok, but for short term only). Glyserol is listed as a + so is OK, but glycerine was not listed.
Does anyone know what the difference between glycerol and glyserine is?
Mark
I obtained a spec sheet for substances that do not re-act with perspex. All the fluids are listed with either a + (Yes), a - (No) or a 0 (Ok, but for short term only). Glyserol is listed as a + so is OK, but glycerine was not listed.
Does anyone know what the difference between glycerol and glyserine is?
Mark
I'd say they are the same....but not completely sure about it,I used gliserina 😉
Have you heard good results usein perspex,does it have anti reflection coating?
The anti reflection coating is important,I can tell from my own and others experience.
The first "test" version I made was from a regular picture frame glass and it was a piece of crap
Have you heard good results usein perspex,does it have anti reflection coating?
The anti reflection coating is important,I can tell from my own and others experience.
The first "test" version I made was from a regular picture frame glass and it was a piece of crap
reflections from lens
I tried a peice of 10mm perspex in front of the lens of the projector and watched a film. I did produce the slightest reflection of anything bright, but this was only on the darkest sceens, IE the begining or end credits. I considered it no worse than rainbow from a DLP. It was not so bad as to make me want to remove it straight away.
As I understand it, the double prism system will have the face of the front prism at an angle to the screen and is not going to run straight across. So here's hoping I'm not to see it or the reflection might be caught inside the casing that will hold the prisms.
Maybe wishfull thinking, but for what this project has cost far, no big loss if it does not work, and if it does, then fantastic...
Mark 🙂
I tried a peice of 10mm perspex in front of the lens of the projector and watched a film. I did produce the slightest reflection of anything bright, but this was only on the darkest sceens, IE the begining or end credits. I considered it no worse than rainbow from a DLP. It was not so bad as to make me want to remove it straight away.
As I understand it, the double prism system will have the face of the front prism at an angle to the screen and is not going to run straight across. So here's hoping I'm not to see it or the reflection might be caught inside the casing that will hold the prisms.
Maybe wishfull thinking, but for what this project has cost far, no big loss if it does not work, and if it does, then fantastic...
Mark 🙂
it works!
My Anamorphic Prism Lens Project
The goal of this project is to be able to watch all of my films at the same height, yet preserve the geometry of the image, so, that for films presented in “scope” ratios like 2.35:1 will be larger than conventional widescreen 1.78:1 letterboxing. It is possible to view both 16:9 (1.78:1) and 21:9 (2.33:1) at the same height from any 16:9 native projector.
IT WORKS! The lens is basically a pair of liquid filled prisms. Each prism is wedge shaped, that when viewed in plan, is based on a right angled triangle of 30/60/90 degrees where each prism (I made mine the same size) is approx 190mm wide by 120mm high.
I have had these prisms made from 6mm (1/4” Perspex) by a plastics engineer and so far this project has set me back just $82.20 and several hours of my time. A commercial equivalent starts at around $1500A with some units costing well past $3000.
As this is my first play, I have elected to fill both prisms with water. Good news, the prisms don’t leak 😀.
To make this work, you must perform a few steps –
1. The source must be set to WIDE or 16:9.
2. The projector must be set to run in both a 4 x 3 mode and a 4 x 3 full panel mode. Note: do not use the mode that stretches the image, that is the job of the lens. I have set up two modes, 1 is 4 x 3 so there are side bars and 2 a full panel 4 x 3 mode. The first mode ( 4 x 3) is used for all 16:9 program. The other mode is used for 21:9 mode. Note that this mode actually clips the top and bottom off the image, but as we do not want to project black bars at the top and bottom of the image, it works to provide us with an image at the same height as the standard 16:9 image.
There are some positives and some negatives (but that goes for almost everything in life), but with some tweaking, I feel confident to say that this is a very cost effective and usable upgrade.
The positives –
1. Very clear images
2. Brighter images of up to 30% (others have measured this with a light meter)
3. Constant height - Wider images for those that SHOULD be wider no black bars top and bottom wasting precious pixels.
4. Variable stretch. If 20:9 becomes a standard with HD DVD, your covered
5. Reduced SDE. I did see some scan lines, but the lens has virtually eliminated all traces of SDE, yet the on screen image is still sharp and clear.
6. Works with all projectors even those with very short throw. This was a point that was brought up with commercial products, that those products did not work with short throw devices. If it works with my horrid HS -3, then it should work with any unit…
7. Very cost effective. So far just $82.20😀
The negatives –
1. Pincushion - Some edge distortion (pincushion) was seen on the left hand side tonight. I feel that by the time I have built the casing and the mounting system, that I should be able to fix this.
2. Barrel distortion - I have been aware of “barrel distortion” for the last few years, and designed a curved screen to correct this.
3. Size and weight – this is a problem if your into neat and tidy. The fact that my projector has a recessed lens caused me to build my prisms large. If the prism is too small, it will chop of the top and or bottom off the image. My prism dimensions are listed above, but should work with a variety of projectors, even those with large lenses…
4. Tilt factor – part of bending light requires the lens to be tilted a fair bit. Again, not too good for the neat and tidy look…
Over all I am impressed with what I have achieved for such a small outlay. I am planning to build a case that will allow both prisms to be adjusted, titled up and down as well as side to side. I should have this part completed early next week and will start to post some images…
Mark
PS I would like to thank Hoxford for starting this thread and the likes of Tor for sharing. This project is looking to be very successful🙂
My Anamorphic Prism Lens Project
The goal of this project is to be able to watch all of my films at the same height, yet preserve the geometry of the image, so, that for films presented in “scope” ratios like 2.35:1 will be larger than conventional widescreen 1.78:1 letterboxing. It is possible to view both 16:9 (1.78:1) and 21:9 (2.33:1) at the same height from any 16:9 native projector.
IT WORKS! The lens is basically a pair of liquid filled prisms. Each prism is wedge shaped, that when viewed in plan, is based on a right angled triangle of 30/60/90 degrees where each prism (I made mine the same size) is approx 190mm wide by 120mm high.
I have had these prisms made from 6mm (1/4” Perspex) by a plastics engineer and so far this project has set me back just $82.20 and several hours of my time. A commercial equivalent starts at around $1500A with some units costing well past $3000.
As this is my first play, I have elected to fill both prisms with water. Good news, the prisms don’t leak 😀.
To make this work, you must perform a few steps –
1. The source must be set to WIDE or 16:9.
2. The projector must be set to run in both a 4 x 3 mode and a 4 x 3 full panel mode. Note: do not use the mode that stretches the image, that is the job of the lens. I have set up two modes, 1 is 4 x 3 so there are side bars and 2 a full panel 4 x 3 mode. The first mode ( 4 x 3) is used for all 16:9 program. The other mode is used for 21:9 mode. Note that this mode actually clips the top and bottom off the image, but as we do not want to project black bars at the top and bottom of the image, it works to provide us with an image at the same height as the standard 16:9 image.
There are some positives and some negatives (but that goes for almost everything in life), but with some tweaking, I feel confident to say that this is a very cost effective and usable upgrade.
The positives –
1. Very clear images
2. Brighter images of up to 30% (others have measured this with a light meter)
3. Constant height - Wider images for those that SHOULD be wider no black bars top and bottom wasting precious pixels.
4. Variable stretch. If 20:9 becomes a standard with HD DVD, your covered
5. Reduced SDE. I did see some scan lines, but the lens has virtually eliminated all traces of SDE, yet the on screen image is still sharp and clear.
6. Works with all projectors even those with very short throw. This was a point that was brought up with commercial products, that those products did not work with short throw devices. If it works with my horrid HS -3, then it should work with any unit…
7. Very cost effective. So far just $82.20😀
The negatives –
1. Pincushion - Some edge distortion (pincushion) was seen on the left hand side tonight. I feel that by the time I have built the casing and the mounting system, that I should be able to fix this.
2. Barrel distortion - I have been aware of “barrel distortion” for the last few years, and designed a curved screen to correct this.
3. Size and weight – this is a problem if your into neat and tidy. The fact that my projector has a recessed lens caused me to build my prisms large. If the prism is too small, it will chop of the top and or bottom off the image. My prism dimensions are listed above, but should work with a variety of projectors, even those with large lenses…
4. Tilt factor – part of bending light requires the lens to be tilted a fair bit. Again, not too good for the neat and tidy look…
Over all I am impressed with what I have achieved for such a small outlay. I am planning to build a case that will allow both prisms to be adjusted, titled up and down as well as side to side. I should have this part completed early next week and will start to post some images…
Mark
PS I would like to thank Hoxford for starting this thread and the likes of Tor for sharing. This project is looking to be very successful🙂
screen shot
Hello to anyone still interested in this thread. My lens has been working well for a few weeks now and I have a collection of 2.35:1 screen shots. Sorry about the noise in this shot, but I could only access a low rez camera...
Thank you to all that posted here. This thread has been the most interesting thing I have read on the net regarding HT and how to improve it in your home...
Mark
Hello to anyone still interested in this thread. My lens has been working well for a few weeks now and I have a collection of 2.35:1 screen shots. Sorry about the noise in this shot, but I could only access a low rez camera...
Thank you to all that posted here. This thread has been the most interesting thing I have read on the net regarding HT and how to improve it in your home...
Mark
Attachments
Nice to hear you are happy with the lens you made.
I'm also more than happy with my lens.This is a good little project for everyone who likes DIYing and can't afford to buy an anamorphic lens.
I still can't believe I paid only 1000euros for my 16:9 projector, dvd player and DIY anamorphic lens.
The picture quality is now deasent ,thanks the lens.
p.s. is that chromatic abberation in your screen shot,or is it just the camera making it?
I'm also more than happy with my lens.This is a good little project for everyone who likes DIYing and can't afford to buy an anamorphic lens.
I still can't believe I paid only 1000euros for my 16:9 projector, dvd player and DIY anamorphic lens.
The picture quality is now deasent ,thanks the lens.
p.s. is that chromatic abberation in your screen shot,or is it just the camera making it?
"is that chromatic abberation in your screen shot,or is it just the camera making it?"
Most of the noise is from the camera, but the left side of the screen does suffer "chromatic abberation"(?) where the image tends to separate into the colour spectrum showing blue on one edge. I have not been able to correct that, though I still have some work to do with my curved screen as well as the actual mounting for both the projector and lens. The image tends to bend half way down on the left side as well. Other than that I am very happy with this project and for what it has cost me, I should not complain at all. This lens has cost just A$150.00 and I have had the prisms made for me by a plastics engineer.
At present I am only using water in both and it works. I also have gone against the recommendation of 30 and 24 degrees by using two 30/60/90 degree prisms.
I want to fill both with glyserine but am having trouble obtaining the 2.5 litres I need to fill both prisms.
Why so big? I have made the lens over size so that it works with my very short throw Sony HS-3. If the prisms were smaller, the recessed lens would prevent this from working.
Cheers,
Most of the noise is from the camera, but the left side of the screen does suffer "chromatic abberation"(?) where the image tends to separate into the colour spectrum showing blue on one edge. I have not been able to correct that, though I still have some work to do with my curved screen as well as the actual mounting for both the projector and lens. The image tends to bend half way down on the left side as well. Other than that I am very happy with this project and for what it has cost me, I should not complain at all. This lens has cost just A$150.00 and I have had the prisms made for me by a plastics engineer.
At present I am only using water in both and it works. I also have gone against the recommendation of 30 and 24 degrees by using two 30/60/90 degree prisms.
I want to fill both with glyserine but am having trouble obtaining the 2.5 litres I need to fill both prisms.
Why so big? I have made the lens over size so that it works with my very short throw Sony HS-3. If the prisms were smaller, the recessed lens would prevent this from working.
Cheers,
Attachments
Update
My anamorphic lens has been up and running for few weeks now and I have no intention of removing it. It makes such a huge difference to the way I now watch movies, both 16:9 (1.78:1 and 1.85:1) and 21:9 (everying else wider than 2.0:1).
I have managed to correct some of the issues I had earlier by re-designing the mount. Though it is not perfect, for less than $200.00, I think this upgrade has been worth every cent...
Mark
My anamorphic lens has been up and running for few weeks now and I have no intention of removing it. It makes such a huge difference to the way I now watch movies, both 16:9 (1.78:1 and 1.85:1) and 21:9 (everying else wider than 2.0:1).
I have managed to correct some of the issues I had earlier by re-designing the mount. Though it is not perfect, for less than $200.00, I think this upgrade has been worth every cent...
Mark
another screen shot
Here is an update. A screen shot from Star Wars 3...
As I said, not bad for less than $200.00 and consider this -
1. I am using an entry level, short throw SONY HS-3.
2. A DIY screen. The white PVC material that laser letters are stuck to.
3. A DIY anamorphic lens - prisms cost just $82.20.
4. Both of the prisms are filled with water and tap water at that!!!
Mark
Here is an update. A screen shot from Star Wars 3...
As I said, not bad for less than $200.00 and consider this -
1. I am using an entry level, short throw SONY HS-3.
2. A DIY screen. The white PVC material that laser letters are stuck to.
3. A DIY anamorphic lens - prisms cost just $82.20.
4. Both of the prisms are filled with water and tap water at that!!!
Mark
Attachments
Wow good job Mark. You are truly a DIY dude.
Consider what I've been contemplating lately.. a contact of mine bought an infocus DLP model, so small and light I couldn't believe it, the output lense was so small I decided to get out an old 32mm projector anamorphic lense I bought on ebay (the type they attached to the projectors in theaters back int he day to stretch the image), and it did a fraiyl good job. The projector was 4:3 and the corners were barely clipped... if the projector was 16:9 it would have been IDEAL! No prisms to fiddle with and leak... I like the idea of just having the lense sitting on some kind of stand in front of the projector and doing the job. I think my ideal now is a good 16:9 projector with a fantastic contrast ratio, and small enough output image that wouldn't be clipped by the lense. Also consider that the cost of these lenses on ebay seemed to average back then around $40 to $80, similar to the cost of building the prisms. My cost for the prisms I dont remember being so high as $80 but it sounds like you really did a top notch job & materials with yours.
IN any case the bottom line has been achieved, home theater essentials for a fraction of what you'd pay for the commercial versions (*panamorph", etc) Home theater is twice as sweet when you DIY !
Consider what I've been contemplating lately.. a contact of mine bought an infocus DLP model, so small and light I couldn't believe it, the output lense was so small I decided to get out an old 32mm projector anamorphic lense I bought on ebay (the type they attached to the projectors in theaters back int he day to stretch the image), and it did a fraiyl good job. The projector was 4:3 and the corners were barely clipped... if the projector was 16:9 it would have been IDEAL! No prisms to fiddle with and leak... I like the idea of just having the lense sitting on some kind of stand in front of the projector and doing the job. I think my ideal now is a good 16:9 projector with a fantastic contrast ratio, and small enough output image that wouldn't be clipped by the lense. Also consider that the cost of these lenses on ebay seemed to average back then around $40 to $80, similar to the cost of building the prisms. My cost for the prisms I dont remember being so high as $80 but it sounds like you really did a top notch job & materials with yours.
IN any case the bottom line has been achieved, home theater essentials for a fraction of what you'd pay for the commercial versions (*panamorph", etc) Home theater is twice as sweet when you DIY !
DIY rules!
Hi Jude,
Thanks for the feedback. I had a plastics engineer construct the prisms out of 6mm Perspex. Though I think that less than $100 is deal anyway! He made them water tight and fitted a removable threaded bung in the top of each expansion chamber. I made the jig and he heated and bent the plastic, then i made a case. For a full run down on my project, go to http://www.hometheaterdiscussion.com/forums/showthread.php?t=5867&page=1&pp=25
This anamorphic lens you bought, what stretch does it have. The Prominar 16H I bought (comes off a 16mm projector) is 2.0:1 stretch, and if you read the thread from the beginning, you will see how I found this site and ultimately built my own 1.33:1 Horizontal stretch lens.
I've been having some fun with this true 2.35:1 lens by turning it 90 degrees and placing in front of a digita camera, then zoom just enough to remove any barreling.
I have been able to capture horizontally squeezed images, then using photo shop, electrically stretch them back to the proper shape. Really cool. I just need to make a mount for the camera and lens so it is a single unit.
True panoramic, none of the normal blown up letter boxing you get at photo labs...
The attached image is the the DIY lens in front of the SONY HS-3. I colour coded it to match the ceilling 🙂
Mark
Hi Jude,
Thanks for the feedback. I had a plastics engineer construct the prisms out of 6mm Perspex. Though I think that less than $100 is deal anyway! He made them water tight and fitted a removable threaded bung in the top of each expansion chamber. I made the jig and he heated and bent the plastic, then i made a case. For a full run down on my project, go to http://www.hometheaterdiscussion.com/forums/showthread.php?t=5867&page=1&pp=25
This anamorphic lens you bought, what stretch does it have. The Prominar 16H I bought (comes off a 16mm projector) is 2.0:1 stretch, and if you read the thread from the beginning, you will see how I found this site and ultimately built my own 1.33:1 Horizontal stretch lens.
I've been having some fun with this true 2.35:1 lens by turning it 90 degrees and placing in front of a digita camera, then zoom just enough to remove any barreling.
I have been able to capture horizontally squeezed images, then using photo shop, electrically stretch them back to the proper shape. Really cool. I just need to make a mount for the camera and lens so it is a single unit.
True panoramic, none of the normal blown up letter boxing you get at photo labs...
The attached image is the the DIY lens in front of the SONY HS-3. I colour coded it to match the ceilling 🙂
Mark
