Hi Mark Techer
I'd like to ask is your "horisontally stretching"lens throwing a second picture somewhere.As my "vertically compressing" lens is throwing one second picture to the ceiling, also one to the back wall but That one I removed with a piece of plastick masking the lens.
p.s. very nice HT setup you have,I specially like the movie theater like speakers.
I'd like to ask is your "horisontally stretching"lens throwing a second picture somewhere.As my "vertically compressing" lens is throwing one second picture to the ceiling, also one to the back wall but That one I removed with a piece of plastick masking the lens.
p.s. very nice HT setup you have,I specially like the movie theater like speakers.
internal light issues
I've fitted some peices of black card agaist the small sides of each prism to stop light leakage.
The image should show the card. Best thing would be to remove the prisms, mask then up and paint small end of each.
I also get some light reflection behind on the back wall as well, but this is not too disctracting as it is never seen on screen...
Its all DIY. Screen, Speakers (all VIFA drivers) Lens...
Mark
I've fitted some peices of black card agaist the small sides of each prism to stop light leakage.
The image should show the card. Best thing would be to remove the prisms, mask then up and paint small end of each.
I also get some light reflection behind on the back wall as well, but this is not too disctracting as it is never seen on screen...
Its all DIY. Screen, Speakers (all VIFA drivers) Lens...
Mark
Attachments
http://www.avsforum.com/avs-vb/showthread.php?p=6286834&&#post6286834
This is a collection of shots at the AVS site...
Mark
This is a collection of shots at the AVS site...
Mark
PHASE II - A 4 prisms lens?
I got to check out the Prismasonic H1200R today and must say that I am very impressed with that product. It is a shame it costs so much. The difference between the H1200 and H600 (upgrades to the older H1000 and H500) are that both the H1000 and the new H1200 have 4 prisms not just 2 like the H600 and the older H500.
The R simply stand for Remote, which has a small twin servo turning the prisms (in pairs) from pass through to strectch.
After using my dual prism anamorphic lens for many weeks, I have considered making a 4 prism version. Has any one tried this?
I am considering spliting each 30/60/90 into two - one at 15/75/90, the other at 15/60/105 by adding a divider to each. Both will be filled throught the same hole at the top in the expansion chamber.
The part that puzzles me is that each pair will face the same way. When I was designing the lens I have now, I learned that the prisms must oppose, or you get severe CA. Given that the second pair will still sit opposite in the case, I am hopping it may cancel out any problems.
Once again, I am getting the plastics engineer to make these new prisms for me, and naturally I will keep you all updated🙂
I have attached an image of what I am thinking of doing...
Any feedback will be welcomed...
Mark
I got to check out the Prismasonic H1200R today and must say that I am very impressed with that product. It is a shame it costs so much. The difference between the H1200 and H600 (upgrades to the older H1000 and H500) are that both the H1000 and the new H1200 have 4 prisms not just 2 like the H600 and the older H500.
The R simply stand for Remote, which has a small twin servo turning the prisms (in pairs) from pass through to strectch.
After using my dual prism anamorphic lens for many weeks, I have considered making a 4 prism version. Has any one tried this?
I am considering spliting each 30/60/90 into two - one at 15/75/90, the other at 15/60/105 by adding a divider to each. Both will be filled throught the same hole at the top in the expansion chamber.
The part that puzzles me is that each pair will face the same way. When I was designing the lens I have now, I learned that the prisms must oppose, or you get severe CA. Given that the second pair will still sit opposite in the case, I am hopping it may cancel out any problems.
Once again, I am getting the plastics engineer to make these new prisms for me, and naturally I will keep you all updated🙂
I have attached an image of what I am thinking of doing...
Any feedback will be welcomed...
Mark
Attachments
Thanks for your kind opinion🙂
I have to admit I was inspired by one of the PRI.....NIC lenses.
The lens is also adjustable,smaller prism has a hinge and comes loose by opening two screws.
Unfortunately I'm not able to take any deacent screen shots with my camera.
The projected picture has some barrel distortion and also is slightly wider from the bottom,as the keystone in my projector is useles.I think the picture also has a little bit of "glare",the black level is sacrificed by this,but it all helps to smoothen the screen door....
I have to admit I was inspired by one of the PRI.....NIC lenses.
The lens is also adjustable,smaller prism has a hinge and comes loose by opening two screws.
Unfortunately I'm not able to take any deacent screen shots with my camera.
The projected picture has some barrel distortion and also is slightly wider from the bottom,as the keystone in my projector is useles.I think the picture also has a little bit of "glare",the black level is sacrificed by this,but it all helps to smoothen the screen door....
I really like your adjustment mount too. Everything matches, nice 🙂
So having successfully built a 2 prism lens, do you have comments or thought on my 4 prisms design? Do you think it will work?
Mark
So having successfully built a 2 prism lens, do you have comments or thought on my 4 prisms design? Do you think it will work?
Mark
Your new project with 4 prisms sounds interesting.is there any other advantage than less chromatic abberation?
If it is only the chromatic abberation I would maybe try first filling your existing prisms with two differend kind of liquids.Like some are using water and terbentine.Or maybe both of them with glyserine.
If it is only the chromatic abberation I would maybe try first filling your existing prisms with two differend kind of liquids.Like some are using water and terbentine.Or maybe both of them with glyserine.
Changing the liquids...
There is a bit of a problem with finding the right Glycerin, as some (the organic ones) a very reactive to bright light. One product was reported to be "volatile" when exposed. This is not what we want with our anamorphic lens 🙂
Given that my prisms are sealed (water tight) I have thought about substituting the water for turpentine as it has a much longer shelf life than most other products and is quite cost effective. I will need to find that list again though that shows what products do/do not re-act with Perspex.
Changing the angles...
During this long but informative thread, the angles found to work best by the early posters were 24 and 30 degrees. They also use dissimilar liquids.
I have proven the two 30 degrees prisms filled with the same liquid can also work.
The next step is big gamble as I am effectively halving the angles and then adding two together to form a new dual prism. When I move my prisms in or out, the edges do change from quite straight to the bad bow I have on the left. My theory on this is due to the amount of displacement of the two prisms, where there is significant air gap between the surfaces. Hopefully the additional two prisms will help reduce the negative effects by progressively stretching the light in smaller steps as the prisms most likely will not need to be displaced as much...
Mark
There is a bit of a problem with finding the right Glycerin, as some (the organic ones) a very reactive to bright light. One product was reported to be "volatile" when exposed. This is not what we want with our anamorphic lens 🙂
Given that my prisms are sealed (water tight) I have thought about substituting the water for turpentine as it has a much longer shelf life than most other products and is quite cost effective. I will need to find that list again though that shows what products do/do not re-act with Perspex.
Changing the angles...
During this long but informative thread, the angles found to work best by the early posters were 24 and 30 degrees. They also use dissimilar liquids.
I have proven the two 30 degrees prisms filled with the same liquid can also work.
The next step is big gamble as I am effectively halving the angles and then adding two together to form a new dual prism. When I move my prisms in or out, the edges do change from quite straight to the bad bow I have on the left. My theory on this is due to the amount of displacement of the two prisms, where there is significant air gap between the surfaces. Hopefully the additional two prisms will help reduce the negative effects by progressively stretching the light in smaller steps as the prisms most likely will not need to be displaced as much...
Mark
pikkujöpö,
Saw your pictures at AVS. Very cool!
http://www.avsforum.com/avs-vb/showthread.php?p=6524246&&#post6524246
DIY lens guys are allowed have show their photos there but just can't discuss it...
Mark
Saw your pictures at AVS. Very cool!
http://www.avsforum.com/avs-vb/showthread.php?p=6524246&&#post6524246
DIY lens guys are allowed have show their photos there but just can't discuss it...
Mark
Thanks Mark 🙂
I wish I could have some day a proper cinema room though.....
Anything new with your lens project?
I was thinking about the liquids used in the DIY lenses.
Maybe there are some other liquids that would work even better than the ones used,like water,terbentine and glyserine.I do not know if they are really good for the purpose.Maybe these liquids are used just because they are easily obtainable household products.
There is one lens made from Panamorph that is liquid filled,It used mineral oil or similar,if I remember correctly.
I wish I could have some day a proper cinema room though.....
Anything new with your lens project?
I was thinking about the liquids used in the DIY lenses.
Maybe there are some other liquids that would work even better than the ones used,like water,terbentine and glyserine.I do not know if they are really good for the purpose.Maybe these liquids are used just because they are easily obtainable household products.
There is one lens made from Panamorph that is liquid filled,It used mineral oil or similar,if I remember correctly.
4 prism lens - update
Hi Pikkujöpö,
Yes, I picked up the new prisms today. He charged me the same price as the last set even though there was a bit more work to these new 2 chamber prisms.
I also started on the new case given that I am reasonably happy with the size and shape. I am making this one in the hope that I can obtain a pass through mode as well as stretch mode. The current one has an alignment issue if you try to make to pass through. Only half the image is on screen. The other half is distorted by the end if the second prism.
So the split prisms work. This worried me a bit given all the previous chat about the angle having to be specific, or it won't work. It does work with the simple tests so far prove that there is enough angle to stretch the image 33%. I have not yet had the chance to run the projector through these prisms, though it would not be that big a deal to change them over from the current single chamber prisms in use right now.
Yes, CA is even finer. I tested this by looking through just 1 prism that I had only filled one side of first and then there was a large decrease in CA when I filled the other side. Even with just one half filled (15 degrees) it stretched beautifully. Then I filled the second prism and placed it in front and there was no CA at all. Even with my two single prism lens, there is some CA if you look at the edges. It appears that a 4 prisms lens fixes that...
I am still looking at different liquids to fill the prisms with. The biggest problem is finding a clear liquid that won't go off (has a long shelf life), is not flammable, and won’t (worse still) ruin the prisms themselves...
So for right now its back to water, but I am going to run some tests in the coming days with some scrap to see what re-acts and what does not. Hopefully by then, I should have the new case all finished as well 🙂
I need to start photo documenting the stages as well so others can see what I have done should they want to go down the 2.35:1 CIH path…
Mark
Hi Pikkujöpö,
Yes, I picked up the new prisms today. He charged me the same price as the last set even though there was a bit more work to these new 2 chamber prisms.
I also started on the new case given that I am reasonably happy with the size and shape. I am making this one in the hope that I can obtain a pass through mode as well as stretch mode. The current one has an alignment issue if you try to make to pass through. Only half the image is on screen. The other half is distorted by the end if the second prism.
So the split prisms work. This worried me a bit given all the previous chat about the angle having to be specific, or it won't work. It does work with the simple tests so far prove that there is enough angle to stretch the image 33%. I have not yet had the chance to run the projector through these prisms, though it would not be that big a deal to change them over from the current single chamber prisms in use right now.
Yes, CA is even finer. I tested this by looking through just 1 prism that I had only filled one side of first and then there was a large decrease in CA when I filled the other side. Even with just one half filled (15 degrees) it stretched beautifully. Then I filled the second prism and placed it in front and there was no CA at all. Even with my two single prism lens, there is some CA if you look at the edges. It appears that a 4 prisms lens fixes that...
I am still looking at different liquids to fill the prisms with. The biggest problem is finding a clear liquid that won't go off (has a long shelf life), is not flammable, and won’t (worse still) ruin the prisms themselves...
So for right now its back to water, but I am going to run some tests in the coming days with some scrap to see what re-acts and what does not. Hopefully by then, I should have the new case all finished as well 🙂
I need to start photo documenting the stages as well so others can see what I have done should they want to go down the 2.35:1 CIH path…
Mark
4 prism lens - update
Tonight I got my older front projector out of its box to conduct some light path tests. There is definitely less CA and the addition of two extra prisms appears to have helped fix that annoying bent left hand side, though that is projector/lens placement dependant...
The placement angles for each dual prisms seem to be the same for the four prisms lens as the conventional 2 prism lens.
The new case is looking more pro too...
Mark
Tonight I got my older front projector out of its box to conduct some light path tests. There is definitely less CA and the addition of two extra prisms appears to have helped fix that annoying bent left hand side, though that is projector/lens placement dependant...
The placement angles for each dual prisms seem to be the same for the four prisms lens as the conventional 2 prism lens.
The new case is looking more pro too...
Mark
Hi Mark
I'm glad to hear the new lens is even better than the old one.
The prisms look very nice.
Maybe you could show a picture of the jig you made for bending the prisms.Looks like you have found a much more leakproof way for making the lens.The one made from glass can be too dificult for many to make and the posibility for leaks is always there(mine did leak at first).
There is some cromatic abberation with my lens.I can see sort of rainbow colours in the text,at the begining and end of the movies.
It doesn't bother me at all when watching the movies though.Maybe with the 4 lens design it could be avoided.
I'm glad to hear the new lens is even better than the old one.
The prisms look very nice.
Maybe you could show a picture of the jig you made for bending the prisms.Looks like you have found a much more leakproof way for making the lens.The one made from glass can be too dificult for many to make and the posibility for leaks is always there(mine did leak at first).
There is some cromatic abberation with my lens.I can see sort of rainbow colours in the text,at the begining and end of the movies.
It doesn't bother me at all when watching the movies though.Maybe with the 4 lens design it could be avoided.
The jig is simply 2 right angled 30/60/90 triangles made from 16mm MDF. There are small slots cut in to each side for the clamps to hold whilst the Perspex cools.
Very simple if you have the skill to work Perspex.
It is just a case of nothing too hard if you put your mind to it...
Mark
Very simple if you have the skill to work Perspex.
It is just a case of nothing too hard if you put your mind to it...
Mark
4 prism lens - update
Ok I had some time spare today to play around with that lens again. Up and till now I have been using the older 2 prism lens as I had some "teething" issues with the 4 prism lens and my short throw projector.
I have basically reversed the prisms where the 90 degree angles face in, not out as they did before. By running the back prism flat across the opening, I have been able to get a true 1.33:1 (I wasn't getting that before with our light reflection problems) and there is no reflection issues. The front prism sticks out a bit, but this set up has also allowed me to get a pass through mode as well as a stretch mode, so I can now re-visit all of my LDs 🙂 some have DTS soundtracks...
I have attached an image from "The Incredibles" that shows the ful screen and you can just make out the speakers...There is a slight wash out in the image, but it is the camera I used tonight...
Mark
Ok I had some time spare today to play around with that lens again. Up and till now I have been using the older 2 prism lens as I had some "teething" issues with the 4 prism lens and my short throw projector.
I have basically reversed the prisms where the 90 degree angles face in, not out as they did before. By running the back prism flat across the opening, I have been able to get a true 1.33:1 (I wasn't getting that before with our light reflection problems) and there is no reflection issues. The front prism sticks out a bit, but this set up has also allowed me to get a pass through mode as well as a stretch mode, so I can now re-visit all of my LDs 🙂 some have DTS soundtracks...
I have attached an image from "The Incredibles" that shows the ful screen and you can just make out the speakers...There is a slight wash out in the image, but it is the camera I used tonight...
Mark
Attachments
Here is a link to the latest developent...
http://www.hometheaterdiscussion.com/forums/showpost.php?p=60004&postcount=58
Mark
http://www.hometheaterdiscussion.com/forums/showpost.php?p=60004&postcount=58
Mark
Some more pictures 🙂
Check out these latest screen shots out.
http://www.hometheaterdiscussion.com/forums/showpost.php?p=60074&postcount=65
Not bad for less than $200.00. I just love DIY...
Mark
Check out these latest screen shots out.
http://www.hometheaterdiscussion.com/forums/showpost.php?p=60074&postcount=65
Not bad for less than $200.00. I just love DIY...
Mark