Craig, Jude,
I just check out the Image Perfect glass at "The Frame Depot" - It is not suitable for anything but pictures. The glass has a depth of field of about 3-4 inches. Anything beyond that gets very fuzzy. Looking through a sample at the store made me think of opening my eyes under water (with out goggles) - everything was blurry after about 4 inches.
I'll try plain glass first.
Darryl
I just check out the Image Perfect glass at "The Frame Depot" - It is not suitable for anything but pictures. The glass has a depth of field of about 3-4 inches. Anything beyond that gets very fuzzy. Looking through a sample at the store made me think of opening my eyes under water (with out goggles) - everything was blurry after about 4 inches.
I'll try plain glass first.
Darryl
That type of glass is probably for UV protection (so that whatever you frame in it is protected from any sunlight, from deteriorating.)
It may be the same stuff I talked to them about. There may be another type, I forget the term now, which is clearer thatn normal glass. I watched Star Wars episode 2 last night and removed my keystone problem from earlier. I still do not have any barrel distortion but for some reason last night I noticed a very feint duplicate reflection of very bright spots of light on the screen itself. I think I need to make a new model with non-glass sides to defeat this.
It may be the same stuff I talked to them about. There may be another type, I forget the term now, which is clearer thatn normal glass. I watched Star Wars episode 2 last night and removed my keystone problem from earlier. I still do not have any barrel distortion but for some reason last night I noticed a very feint duplicate reflection of very bright spots of light on the screen itself. I think I need to make a new model with non-glass sides to defeat this.
The type of mineral oil I used had a label of the store itself. There were no other types to choose from that I could tell at the store I went to (a common pharmacy chain here in the USA)
It was "Walgreen" brand mineral oil. I will try to get some more specifics tonight from the label on the bottle. I wonder if possibly all the different mineral oils they had have the same "refractive index" ? (maybe try buying the cheapest, most common, first)
It was "Walgreen" brand mineral oil. I will try to get some more specifics tonight from the label on the bottle. I wonder if possibly all the different mineral oils they had have the same "refractive index" ? (maybe try buying the cheapest, most common, first)
I used water in one (larger) and mineral oil in the other (closer, smaller prism). As I understood it from talks with you Tor and other research, both have "chromatic abboration" unless you use them both together to cancel it out. I am curious though because the commercial model has both prisms filled with oil if I understand correctly.
By the way I did notice barrel distortion start to occur when I tried to squeeze the 16:9 image even further by tilting the front prism further. Even if the distortion is somewhat signficant I'm probably still interested in getting a full panel 2.35 film and just cropping the top off the image with masking.
Not sure if I'll make a second DIY screen that is 2.35 or just jimmy-rig my existing 16:9 screen so that I can quickly adjust it to 2.35 as needed.
By the way I did notice barrel distortion start to occur when I tried to squeeze the 16:9 image even further by tilting the front prism further. Even if the distortion is somewhat signficant I'm probably still interested in getting a full panel 2.35 film and just cropping the top off the image with masking.
Not sure if I'll make a second DIY screen that is 2.35 or just jimmy-rig my existing 16:9 screen so that I can quickly adjust it to 2.35 as needed.
By the way Tor now that you're interested in this project again I'm really curious if you (or all of us, together) can figure out some angles for optimal 2.35 -- I sent a pm to 'decinema' on avsforum to see if he knows. I'll post anything I can find.
IDEA: If the existing model prisms we are creating can be merely rotated futher to form a 2.35 squeeze -- with a similar amount of barrel distortion as the 'commercial model' -- seems to me you could make a new design that simply had the two prisms both independently rotatable... and marks on the side of the frame to designate where to turn them depending on which squeeze ratio you wanted. (thereby only needing the one lens to accomplish either).
Tor: On this subject, have you gotten an HTPC up and running yet or are you still using a standalone DVD player?
IDEA: If the existing model prisms we are creating can be merely rotated futher to form a 2.35 squeeze -- with a similar amount of barrel distortion as the 'commercial model' -- seems to me you could make a new design that simply had the two prisms both independently rotatable... and marks on the side of the frame to designate where to turn them depending on which squeeze ratio you wanted. (thereby only needing the one lens to accomplish either).
Tor: On this subject, have you gotten an HTPC up and running yet or are you still using a standalone DVD player?
I have no idea how to calculate the angles, I don't have the math-smarts to figure out the formulas for myself. 
I wanted to try making a lens with hinged prisms, but I fear it may be a waste of time. If such a lens is to be made the prisms will need to be re-designed a little. I don't mean the angles, but you need to make sure that the edges have enough room for the picture as you rotate the prism. The peak tip of the waterprism will need to be higher or else when you tilt the prism down it will interfere with the picture.... I think.
I'm still using my standalone DVD-player, My projector had been away for three months so I kinda lost interest. But seeing the picture quality with my new ATi 9700 PRO I'm gonna build one when I have the money. The ATi kicks GeForce2 GTS bee-hind!
Tor Arne
I wanted to try making a lens with hinged prisms, but I fear it may be a waste of time. If such a lens is to be made the prisms will need to be re-designed a little. I don't mean the angles, but you need to make sure that the edges have enough room for the picture as you rotate the prism. The peak tip of the waterprism will need to be higher or else when you tilt the prism down it will interfere with the picture.... I think.
I'm still using my standalone DVD-player, My projector had been away for three months so I kinda lost interest. But seeing the picture quality with my new ATi 9700 PRO I'm gonna build one when I have the money. The ATi kicks GeForce2 GTS bee-hind!
Tor Arne
After reading about this for some time, I finally decided to make a lens for myself.
I used mineral oil and the 24° angle.
It doesn't work well at all. Maybe I made it wrong. The image cannot be focused, the red and blue colors are seperating (even when simply looking through the lens) and it also creates a very bad barrel distortion (it bows extremely). To sum it up, the image is unwatchable.
I still don't know a lot about making these, so if anyone has explinations as of why these discrepancies occur, it would be most helpful if I were to make another.
I used mineral oil and the 24° angle.
It doesn't work well at all. Maybe I made it wrong. The image cannot be focused, the red and blue colors are seperating (even when simply looking through the lens) and it also creates a very bad barrel distortion (it bows extremely). To sum it up, the image is unwatchable.
I still don't know a lot about making these, so if anyone has explinations as of why these discrepancies occur, it would be most helpful if I were to make another.
Exactly!
You need to make two prisms with the peak-angles 24° for the oilprism and 30° for the waterprism. The peak-angle is the angle of the two paces of the prism.
And they then have to be mounted with specific angles relative to each other. This drawing describes what angles they are mounted relative to a vertical line. The oilprism should be mounted at an angle of 3,2° and the waterprism should be mounted at an angle of 31° relative to the vertical line.
In this illustration the projector is table-mounted on the left side of the prisms and the light goes from left to right. For a ceiling mounted projector it should be upside-down.
This next picture shows a complete optial assembly for one of my first lenses. It has the oilprism and waterprism glued together at the right angles with some aluminium pieces. The whole thing is then inserted into the housing.
Tor Arne
You need to make two prisms with the peak-angles 24° for the oilprism and 30° for the waterprism. The peak-angle is the angle of the two paces of the prism.
And they then have to be mounted with specific angles relative to each other. This drawing describes what angles they are mounted relative to a vertical line. The oilprism should be mounted at an angle of 3,2° and the waterprism should be mounted at an angle of 31° relative to the vertical line.
An externally hosted image should be here but it was not working when we last tested it.
In this illustration the projector is table-mounted on the left side of the prisms and the light goes from left to right. For a ceiling mounted projector it should be upside-down.
This next picture shows a complete optial assembly for one of my first lenses. It has the oilprism and waterprism glued together at the right angles with some aluminium pieces. The whole thing is then inserted into the housing.
An externally hosted image should be here but it was not working when we last tested it.
Tor Arne
I finished up the water prism yesterday. I have to say, it all works pretty good!
The prisms aren't exactly secured yet. I made a small wire frame to rest the two on in the correct angle just to see if they would work. And sure enough, they did.
There is a slight barrel distortion, and the image isn't as sharp as without them, but it is definately watchable and very film-like.
*
I thought you all might be interested in how I constructed it:
I based it all on the PVC tube mentioned here a couple pages back. I found a clear plastic box at a craft store and cut out a 30° and 24° angled triangle from it. I left the sides intact and only had to glue the glass areas on. Since only the glass is the glued part, that's the only areas that I need to worry about leaks, if any occur. After a week with the oil prism and almost two days with the water, both with no leaks, they seem to be sealed perfectly.
Construction of the prisms were not at all as hard as I thought they would be when I first started looking into it. I still need to make the housing, but it's nice to see them in action even though there is some reflecting on the ceiling and such...since they are just sitting there "naked" in front of my projector.
I didn't spend a whole lot of money on either of the prisms. This was to be a test for myself to see if it was worth the hassel to make good ones. Both together came to about $30 USD. It would have been about $15 or $20 but I had to buy more picture frames for the glass because I kept breaking them while trying to cut them. I finally got the technique down with the final cut, though. But in all, $30 beats the $1800 for the Panamorph.
*
All in all, it was a worth while expirence to make these. I'm looking forward to mounting them correctly for a finished product.
Thanks for everones input. I could never have done this without the information provided here.
The prisms aren't exactly secured yet. I made a small wire frame to rest the two on in the correct angle just to see if they would work. And sure enough, they did.
There is a slight barrel distortion, and the image isn't as sharp as without them, but it is definately watchable and very film-like.
*
I thought you all might be interested in how I constructed it:
I based it all on the PVC tube mentioned here a couple pages back. I found a clear plastic box at a craft store and cut out a 30° and 24° angled triangle from it. I left the sides intact and only had to glue the glass areas on. Since only the glass is the glued part, that's the only areas that I need to worry about leaks, if any occur. After a week with the oil prism and almost two days with the water, both with no leaks, they seem to be sealed perfectly.
Construction of the prisms were not at all as hard as I thought they would be when I first started looking into it. I still need to make the housing, but it's nice to see them in action even though there is some reflecting on the ceiling and such...since they are just sitting there "naked" in front of my projector.
I didn't spend a whole lot of money on either of the prisms. This was to be a test for myself to see if it was worth the hassel to make good ones. Both together came to about $30 USD. It would have been about $15 or $20 but I had to buy more picture frames for the glass because I kept breaking them while trying to cut them. I finally got the technique down with the final cut, though
. But in all, $30 beats the $1800 for the Panamorph.*
All in all, it was a worth while expirence to make these. I'm looking forward to mounting them correctly for a finished product.
Thanks for everones input. I could never have done this without the information provided here.
Is picture frame glass the right glass to use? I thought that it would do exactally what your problem describes, giving you a blurry image. Museum or high end glass will give a much better picture. Someone correct me if I am wrong.
Also, where did you find the square plastic tube? Also, what size did you buy to make this work? Thanks.
Craig Carrigan
Also, where did you find the square plastic tube? Also, what size did you buy to make this work? Thanks.
Craig Carrigan
I doubt picture frame glass is what should be used for these. I used it only because I wanted to see if they were worth the time to make good ones. And I proved to myself that they are.
They may be unfocused just a tad, but not enough to notice it at all when watching a movie. When I pull down the menu of my projector, that's when I can tell that it's out of focus just a little bit.
The prisms I made are both the exact same size. They are about 3.5" tall and wide. I have a long throw on my projector, so these are both big enough. These would not fit short throw projectors.
I didn't buy a tube. I bought a clear plastic box from a local craft store. It was most likely made to hold buttons or small things in it. I, of course, hacked it apart.
They may be unfocused just a tad, but not enough to notice it at all when watching a movie. When I pull down the menu of my projector, that's when I can tell that it's out of focus just a little bit.
The prisms I made are both the exact same size. They are about 3.5" tall and wide. I have a long throw on my projector, so these are both big enough. These would not fit short throw projectors.
I didn't buy a tube. I bought a clear plastic box from a local craft store. It was most likely made to hold buttons or small things in it. I, of course, hacked it apart.
Thanks for the quick response. I wasn't aware that this was a mock up model to see if it would work.
Also, what is everyone else using to fill these containers? Do you just punch a couple of holes in the side? Do you put some pipe in there? What have you found that works the best? Thanks. I'm going to stop by some shops and look for a plastic box to start my second batch (first one leaked real bad). Also, where might I find mineral oil for this project? I have turpentine but I think I may want to go with something that won't explode and kill me
Craig
Also, what is everyone else using to fill these containers? Do you just punch a couple of holes in the side? Do you put some pipe in there? What have you found that works the best? Thanks. I'm going to stop by some shops and look for a plastic box to start my second batch (first one leaked real bad). Also, where might I find mineral oil for this project? I have turpentine but I think I may want to go with something that won't explode and kill me
Craig
I just want to let you know that the idea and all calculations are from the beisammen.de user "theother". You can check the 59 pages thread here:
http://212.105.197.47/vbportal/forums/showthread.php?s=&threadid=4725&perpage=15&pagenumber=1
You can download the excel file here:
http://212.105.197.47/vbportal/download.php?op=viewdownload&cid=2
-> Prisma Berechnung "Theother"
Have fun
http://212.105.197.47/vbportal/forums/showthread.php?s=&threadid=4725&perpage=15&pagenumber=1
You can download the excel file here:
http://212.105.197.47/vbportal/download.php?op=viewdownload&cid=2
-> Prisma Berechnung "Theother"
Have fun
I bought everything, except for the plastic box and epoxy, at a supermarket:
A few cheap picture frames, distilled water, mineral oil, a protractor and a meat juice needle (I forget what it's called).
My grandfather is deeply into building radio controlled airplanes, so he had plenty of epoxy and tools. I cut the plastic on his ban saw where I was able angle the table to the desired degree. I then rubbed it carefully on a sheet of sandpaper to smooth out the edges and to be sure the angles were correct.
The glass fit extremely well and very flush against the plastic, so glueing it was an easy task without much concern for leaks.
I applied a bead of the two step epoxy with a small dowl (a little thicker than a toothpick) around the edge of the plastic. Then placed the glass on top of it and put a small but heavy object on it for pressure while it dried for an hour.
Filling it, I used the meat juice needle and only one hole which I had drilled into one plastic side before I started glueing. By the way, I suggest filling the water prism first as the minerial oil was a pain to clean out of the needle. I did end up with a small bubble in each of the prisms when glueing the hole cap on it. No bother, each bubble is very small and is completely out of the way when I'm usuing the prisms.
All that's left is to make a housing to hold the prisms in place.
A few cheap picture frames, distilled water, mineral oil, a protractor and a meat juice needle (I forget what it's called).
My grandfather is deeply into building radio controlled airplanes, so he had plenty of epoxy and tools. I cut the plastic on his ban saw where I was able angle the table to the desired degree. I then rubbed it carefully on a sheet of sandpaper to smooth out the edges and to be sure the angles were correct.
The glass fit extremely well and very flush against the plastic, so glueing it was an easy task without much concern for leaks.
I applied a bead of the two step epoxy with a small dowl (a little thicker than a toothpick) around the edge of the plastic. Then placed the glass on top of it and put a small but heavy object on it for pressure while it dried for an hour.
Filling it, I used the meat juice needle and only one hole which I had drilled into one plastic side before I started glueing. By the way, I suggest filling the water prism first as the minerial oil was a pain to clean out of the needle. I did end up with a small bubble in each of the prisms when glueing the hole cap on it. No bother, each bubble is very small and is completely out of the way when I'm usuing the prisms.
All that's left is to make a housing to hold the prisms in place.
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