Basically I'm making a plano-concave lens.
Its going to be the horizontally expanding type, not the vertically shrinking type.
So let me get this straight:
You never attempted to make a cylindrical lens, you just tried to bend the lexan around a corner?
That isn't what I am doing
There are 2 pieces of lexan in this design, the top slightly curved one and the bottom flat one. Actually, the bottom piece doesn't even have to be lexan, because there is no curve in it, but I'm using lexan anyways cause i have alot of it lying around.
Its going to be the horizontally expanding type, not the vertically shrinking type.
So let me get this straight:
You never attempted to make a cylindrical lens, you just tried to bend the lexan around a corner?
That isn't what I am doing
There are 2 pieces of lexan in this design, the top slightly curved one and the bottom flat one. Actually, the bottom piece doesn't even have to be lexan, because there is no curve in it, but I'm using lexan anyways cause i have alot of it lying around.
Attachments
Yes that's correct.... I've only made attempts (both unsucessful and sucessful) at the typical/popular anamorphic lense design w/ two separate prisms.
I only interjected my thoughts to you/others because I wanted to give you a heads up of what you might experience or expect when you bend and/or apply heat to your lexan and expect certain results from the image passing through it. Also because that seems to be the subject at hand here-- DIY anamorphic.
In my case the lexan was put over heat and bent to the appropriate angles. I also had two separate pieces that were bonded together, but to form more of a prism shape. Both were bent over heat but the side pieces didn't much matter since light wasn't passing through them. So.. ultimately I did more than just bend it around a corner, I actually built a prism with it, filled it with oil/water and gave it a go.
Being unfamiliar with what a "plano concave lense" is specifically, I still cannot picture in my head it's shape in relation to your bracket that you attach in your email. Is it just a cylindrical-shaped (created by bending) piece of lexan that rests neatly into the curved portion of your bracket, like a telescope? I don't suppose this could be correct because you say it will eventually have a flat bottom that rests in the square space at the bottom of the bracket.
Another piece of info I got just yesterday is they have two types of lexan, "extruded" and "cast". Extruded formed the shapes by pushing the material through a shape. The "cast" variety is formed by pouring into a mold. "Cast" seems like it may be a better choice for those of us using it for lenses, because, as I was told by a plastics specialist, it isnt bound to have as many artifacts inside the solid piece once it solidifies.
I only interjected my thoughts to you/others because I wanted to give you a heads up of what you might experience or expect when you bend and/or apply heat to your lexan and expect certain results from the image passing through it. Also because that seems to be the subject at hand here-- DIY anamorphic.
In my case the lexan was put over heat and bent to the appropriate angles. I also had two separate pieces that were bonded together, but to form more of a prism shape. Both were bent over heat but the side pieces didn't much matter since light wasn't passing through them. So.. ultimately I did more than just bend it around a corner, I actually built a prism with it, filled it with oil/water and gave it a go.
Being unfamiliar with what a "plano concave lense" is specifically, I still cannot picture in my head it's shape in relation to your bracket that you attach in your email. Is it just a cylindrical-shaped (created by bending) piece of lexan that rests neatly into the curved portion of your bracket, like a telescope? I don't suppose this could be correct because you say it will eventually have a flat bottom that rests in the square space at the bottom of the bracket.
Another piece of info I got just yesterday is they have two types of lexan, "extruded" and "cast". Extruded formed the shapes by pushing the material through a shape. The "cast" variety is formed by pouring into a mold. "Cast" seems like it may be a better choice for those of us using it for lenses, because, as I was told by a plastics specialist, it isnt bound to have as many artifacts inside the solid piece once it solidifies.
A plano-concave cylindrical lens is just a lens that is planar (flat) on one side, and concave on the other
That is correct, the lexan is going to rest in the curved portion of the bracket, but there is also going to be a second piece of lexan mounted on the bottom of that bracket
That is correct, the lexan is going to rest in the curved portion of the bracket, but there is also going to be a second piece of lexan mounted on the bottom of that bracket
Boys and girls, if I were looking to buy a surplus anamorphic lens what kind of specs would I would be looking for? For instance rear diameter, front diameter, length of lens etc..?
Also when we are talking about using a anamorphic projection lens are we talking about unsqueezing only 2.35:1 movies or 1:85 squeezed dvds or both. I would image you would need 2 seperate for the 2 different formats.
Another thing. I just realized that without an anamorphic lens my 2:35 movie would be seen with 220,595 pixels. I slap the anamorphic on and I am watching 414,720 pixels. This is a huge difference. Why is this not a bigger topic on this board?
Also when we are talking about using a anamorphic projection lens are we talking about unsqueezing only 2.35:1 movies or 1:85 squeezed dvds or both. I would image you would need 2 seperate for the 2 different formats.
Another thing. I just realized that without an anamorphic lens my 2:35 movie would be seen with 220,595 pixels. I slap the anamorphic on and I am watching 414,720 pixels. This is a huge difference. Why is this not a bigger topic on this board?
There was a post on avsforum about this subject of using old anamorphic lenses, one guy knew a lot about this and if you do a search you'll probably find the thread. I purchased one on EBAY and although it did work, it clipped the corners, so, the size of it does matter. The bigger the better.
On your other question ... the most popular version of the lense squeezes both, if you are watching 2.35 of course you still aren't using all your pixels. A 2.35 commercial version of the lense does exist which only works with 2.35, using your full panel. Some folks use both. I'm working on a design which will be both in one, but would need to be tilted/adjusted when you watch one or the other. As discussed in this thread the angle needs to be steeper and there will most likely be more bowing as a result.
I agree that's a huge difference in pixels and PQ, if you can get a lense to compress to 2.35. I HAS been traditionally a popular topic on avsforum talking about the commercial version of this lense. One thing that I believe works though I haven't seen it, is some folks who have a 16:9 native projector, can use the standard version of the lense (DIY or otherwise) to condense to 2.35 using the full panel.
On your other question ... the most popular version of the lense squeezes both, if you are watching 2.35 of course you still aren't using all your pixels. A 2.35 commercial version of the lense does exist which only works with 2.35, using your full panel. Some folks use both. I'm working on a design which will be both in one, but would need to be tilted/adjusted when you watch one or the other. As discussed in this thread the angle needs to be steeper and there will most likely be more bowing as a result.
I agree that's a huge difference in pixels and PQ, if you can get a lense to compress to 2.35. I HAS been traditionally a popular topic on avsforum talking about the commercial version of this lense. One thing that I believe works though I haven't seen it, is some folks who have a 16:9 native projector, can use the standard version of the lense (DIY or otherwise) to condense to 2.35 using the full panel.
Thanks. How wide was your lens where the clipping was hapening?
Also I noticed some of these anamorphic things on ebay and the net are refered to as anamorphic attachment. Does this mean they are ussually used in conjunction with a standard projection lens. What I noticed is that most of these anamorphic lenses have a much shorter focal length then diylabs triplet lens of 300mm or so and even this is not long enough for 15 inch panels.
Did you replace your standard 4:3 lens with the anamorphic lens or did you add it as an attachment? What was the focal length and what was the throw?
Thanks
Also I noticed some of these anamorphic things on ebay and the net are refered to as anamorphic attachment. Does this mean they are ussually used in conjunction with a standard projection lens. What I noticed is that most of these anamorphic lenses have a much shorter focal length then diylabs triplet lens of 300mm or so and even this is not long enough for 15 inch panels.
Did you replace your standard 4:3 lens with the anamorphic lens or did you add it as an attachment? What was the focal length and what was the throw?
Thanks
I have since re-sold the lense on ebay (I didn't lose any money ont he deal, bought for $30 sold for around the same) so unfortunately I don't have the measurements any longer. I didn't pay too close attention to it as I was focusing on building the DIY version of the commercial "lense"
I think the majority of pieces you can find on ebay that are anamorphic attachments are meant to either thread onto the end of a camera or on the end of a theater projector. The back of my lense had a thread and was meant to be put onto the projector for anamoprhic films and I suppose removed for the standard "flat" films. So yes, I think they were used in conjunction with another standard lense, which alone probably just set focus (and other things?)
When I used the lense I purchased on ebay I didn't replace my existing 4:3 lense I just held it in place in front of the 4:3 lense. I'm not sure now how it affected the throw. I'm fairly certain it didn't affect my throw much at all, I didn't pay too close attention to all of the other details like focal length, etc, because the corners were clipped and I just abandoned it as a solution quickly. If you do find some standard surplus lense manufcaturer and model # that works well for most HT projectors, do let us know !! The one I think that was posted on AVSFORUM was "SUPER MAGNA" or something similar, and he did post specifics there on the widths/focal lengths you needed. I could never find it in any searches I did at the time. I'm satisfied with what the DIY version can do so I didn't really pursue it further.
I think the majority of pieces you can find on ebay that are anamorphic attachments are meant to either thread onto the end of a camera or on the end of a theater projector. The back of my lense had a thread and was meant to be put onto the projector for anamoprhic films and I suppose removed for the standard "flat" films. So yes, I think they were used in conjunction with another standard lense, which alone probably just set focus (and other things?)
When I used the lense I purchased on ebay I didn't replace my existing 4:3 lense I just held it in place in front of the 4:3 lense. I'm not sure now how it affected the throw. I'm fairly certain it didn't affect my throw much at all, I didn't pay too close attention to all of the other details like focal length, etc, because the corners were clipped and I just abandoned it as a solution quickly. If you do find some standard surplus lense manufcaturer and model # that works well for most HT projectors, do let us know !! The one I think that was posted on AVSFORUM was "SUPER MAGNA" or something similar, and he did post specifics there on the widths/focal lengths you needed. I could never find it in any searches I did at the time. I'm satisfied with what the DIY version can do so I didn't really pursue it further.
I have had no luck finding any references to used or old anamorphic lenses info on avsforum. Everything I found so far was about expensive lenses for commercial projectors.
I found panamorph on ebay for hundreds but not the super magna or something anywhere.
I found panamorph on ebay for hundreds but not the super magna or something anywhere.
Now you know how I felt when I set out to look for one as well. If you find any surplus anamorphic lenses on ebay any one of them might very well work if you can figure out the specifics you need, hwoever, I think it's more of a rarity to find one wide enough to work, since most of the equipment is probably close to a certain standard which would in most cases be too narrow not to clip the edges.
The panamorph on ebay is a "good" deal because I think if you go buy one new from www.panamorph.com I think it's over $1000. On the other hand, you can probably find it for cheaper if you dig deep enough. And, of course, for less than $30 in materials you just build your own which works almost identically. Email me if you like barnes_jude@yahoo.com
The panamorph / DIY version is very different than the surplus lenses you were talking about, which are solid glass or lexan, the DIY/panamorph are two prisms filled with liquids to do the work on the image.
The panamorph on ebay is a "good" deal because I think if you go buy one new from www.panamorph.com I think it's over $1000. On the other hand, you can probably find it for cheaper if you dig deep enough. And, of course, for less than $30 in materials you just build your own which works almost identically. Email me if you like barnes_jude@yahoo.com
The panamorph / DIY version is very different than the surplus lenses you were talking about, which are solid glass or lexan, the DIY/panamorph are two prisms filled with liquids to do the work on the image.
anamorphic convex lens design
Psionic: I like your idea for the concave lens. I am wanting to expand my image horizontally though, if I made a convex lens like yours would this work? How do I figure out what dimensions and index of curvature it would need to be? Also wouldn't a lens like this refract each color of light differently and produce a chromatically blurred image? Perhaps this is why there are no lens designs like this.
Psionic: I like your idea for the concave lens. I am wanting to expand my image horizontally though, if I made a convex lens like yours would this work? How do I figure out what dimensions and index of curvature it would need to be? Also wouldn't a lens like this refract each color of light differently and produce a chromatically blurred image? Perhaps this is why there are no lens designs like this.
Has anyone tried to make the lenses out of solid glass or acrylic and then corrected for the color abberations in the software. This should be possible if running with a PC.
Hezz
Hezz
Have you guys ever considered hand grinding a small surface correction area in a thicker piece of optical acrylic instead of bending the lexan. If you bend the lexan it will have to be annealled or else surface tension in the plastic will create distortions.
You can anneal it be putting the bend piece of plastic in a hot oven but not letting the temperature get hot enough to melt the plastic. Leave it there for a few hours to let the plastic structure relax.
Hezz
You can anneal it be putting the bend piece of plastic in a hot oven but not letting the temperature get hot enough to melt the plastic. Leave it there for a few hours to let the plastic structure relax.
Hezz
hezz
yeah that might work, with all of this lens fooling im seeing on here in the last day i bet u would have a party at my house hezz, i have heaps of all kinds of lenses i bet u would love to just fool with lol, i have one that would suit this job too, ill have to fool around abit more after i do this projector, i nearly made a zoom lens a few months ago but i decided to get this projector going instead.
Trev
yeah that might work, with all of this lens fooling im seeing on here in the last day i bet u would have a party at my house hezz, i have heaps of all kinds of lenses i bet u would love to just fool with lol, i have one that would suit this job too, ill have to fool around abit more after i do this projector, i nearly made a zoom lens a few months ago but i decided to get this projector going instead.
Trev
Hezz: Would you need that 2nd plano convex lens? Will one convex lens work or would it produce chromatic abberations or distort the image somehow?
I don't know much about optics, just what I learned in physics, so I don't know specifics, but have lots of ideas 🙂.
I think it is very possible to correct the chormatic abberations in software, but I don't know how you'd interface with the DVD programatically.
Is it possible that some types of fluid used to fill a lense refracts all light evenly, this way you wouldn't have chromatic abberations.
I don't know much about optics, just what I learned in physics, so I don't know specifics, but have lots of ideas 🙂.
I think it is very possible to correct the chormatic abberations in software, but I don't know how you'd interface with the DVD programatically.
Is it possible that some types of fluid used to fill a lense refracts all light evenly, this way you wouldn't have chromatic abberations.
Z2895,
I was expressing two different ideas. One was based on the prismatic anamorphic lens where the lenses are mode hollow and filled with different liquid materials to adjust their index of refaction. Because the prisms create a color shift. Making the hollow prisms so they don't leak and and use up much light seems to be two difficulties that some are experiencing. I thought that if you could make the prisms out of solid material they could be made easily. Like out of solid acrylic. But there would have to be a way to adjust the color shift. It could be done in software as far as I know if you are using a computer to drive your projector.
The other ideas was a way to make an ajustable anamorphic lens but no provision for chromatic abberations is noted or assumed by that drawing.
I'm thinking that if the lens shapes could be optimised then It might be possible to have a variable adjust anamorphic lens. That is what the middle lens is for in that drawing. It does not need to be there for a projection system to work. I was just illustrating a concept.
Hezz
I was expressing two different ideas. One was based on the prismatic anamorphic lens where the lenses are mode hollow and filled with different liquid materials to adjust their index of refaction. Because the prisms create a color shift. Making the hollow prisms so they don't leak and and use up much light seems to be two difficulties that some are experiencing. I thought that if you could make the prisms out of solid material they could be made easily. Like out of solid acrylic. But there would have to be a way to adjust the color shift. It could be done in software as far as I know if you are using a computer to drive your projector.
The other ideas was a way to make an ajustable anamorphic lens but no provision for chromatic abberations is noted or assumed by that drawing.
I'm thinking that if the lens shapes could be optimised then It might be possible to have a variable adjust anamorphic lens. That is what the middle lens is for in that drawing. It does not need to be there for a projection system to work. I was just illustrating a concept.
Hezz
Thanks for your further explanations, I understand what your saying, I see how you want to build a lense as described in your other thread, I like the pics and am glad you're posting, its interesting to read.
Now for some questions not directly related to your project(s).
Would a lense (cylindrical convex) used to horizontally expand a projector image distort the image and/or produce chromatic abberations?
I am interested in making a lense similiar to Psionic, but don't want to start it if it's not going to work. The reason I don't think it will work from my limited experience with lenses is if a prism produces chromatic abberation, then why wouldn't any other shape of a lense made with the same material? Thanks for any help.
Now for some questions not directly related to your project(s).
Would a lense (cylindrical convex) used to horizontally expand a projector image distort the image and/or produce chromatic abberations?
I am interested in making a lense similiar to Psionic, but don't want to start it if it's not going to work. The reason I don't think it will work from my limited experience with lenses is if a prism produces chromatic abberation, then why wouldn't any other shape of a lense made with the same material? Thanks for any help.
A single cylindricat lense would introduce a lot of chromatic abberation.
The two-prism anamorphic lenses in the other thread are not hard to make. The reason there are two prisms is not to get the right compression. The reason is to eliminate chromatic abberation.
The two-prism anamorphic lenses in the other thread are not hard to make. The reason there are two prisms is not to get the right compression. The reason is to eliminate chromatic abberation.
Tahustvedt,
Could a miniscus acylindrical lens be used in the above diagrame to offset the chromatic abberations to some extent. Assuming such a lens could be manufactured.
Ace and Tah,
How much chromatic abberation would that simple lens cause in the set up. Could it be corrected in software or would be be too extensive?
Z2895,
I think pisonics design is a plano concave that he intents to expand the horizontal image with. It would accomplish the same thing but to me it makes more sense to compress the vertical rather than expand the horizontal because then you gain resolution effective resolution.
Hezz
Could a miniscus acylindrical lens be used in the above diagrame to offset the chromatic abberations to some extent. Assuming such a lens could be manufactured.
Ace and Tah,
How much chromatic abberation would that simple lens cause in the set up. Could it be corrected in software or would be be too extensive?
Z2895,
I think pisonics design is a plano concave that he intents to expand the horizontal image with. It would accomplish the same thing but to me it makes more sense to compress the vertical rather than expand the horizontal because then you gain resolution effective resolution.
Hezz
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